Boston Regional Intelligence Center/AP

By MICHAEL FALCONE ( @michaelpfalcone )

NOTABLES

• ABC NEWS' LIVE SPECIAL REPORT ON THE UNFOLDING SITUATION IN BOSTON: http://abcn.ws/livenews1

• ONE MARATHON BOMBING SUSPECT DEAD, MANHUNT FOR SECOND: One suspect in this week's deadly Boston Marathon bombing was killed after a police shootout, and a second suspect, identified by officials as Dzhokhar Tsarnaev, remains at large and the subject of a massive manhunt, police said early this morning. ABC's PIERRE THOMAS, BRIAN ROSS, ANTHONY CASTELLANO AND LEE FERRAN report that Tsarnaev, the man the FBI identified Thursday only as Suspect 2 in photos related to the marathon bombing investigation, is on the loose and is armed and dangerous, police said. The 19-year-old is the target of a "massive manhunt," Massachusetts Gov. Deval Patrick said today. The suspect is believed to be armed with an assault-style rifle and an assortment of other weapons, including bombs, a senior federal law enforcement official said today. There is great concern that Tsarnaev might try to take hostages, the official said. http://abcn.ws/XUGy9R

• WHAT HAPPENED OVERNIGHT: Police said the violent ordeal began around 10:30 p.m. Thursday evening when a 7-Eleven convenience store was robbed in Cambridge, Mass., shortly before an MIT campus police officer was shot. The suspects then hijacked a Mercedes and drove to Watertown, Mass. while being pursued by police. The chase ended in a firefight that left one suspect dead, while the other managed to slip away, police said. Federal law enforcement sources told ABC News the suspects admitted their role in the Boston Marathon bombing to the carjack victim. Now, the city of Watertown has been effectively shut down, ABC's CHRISTINA NG reports. Public transportation has been suspended and authorities told people at closed stops and stations to go home. No vehicle traffic is allowed. A no-fly zone is in place over the city. http://abcn.ws/11JEBve

• PARAMILITARY TRAINING? The suspects are believed to be brothers from Russia and of Chechen ethnicity, ABC's PIERRE THOMAS and JACK DATE report. They had been in the United States for at least two years and, because of the skill with which they engaged police, likely had paramilitary training, federal law enforcement sources told ABC News. A law enforcement source confirmed that at least one of the brothers is a legal permanent resident in the United States. The brothers are believed to have spent time in Kyrgyzstan.

• CITY-WIDE SHELTER IN PLACE: From Boston Mayor Thomas Menino earlier this morning: "The City of Boston is urging City-wide shelter in place. As this investigation unfolds we are advising all residents, citywide, to shelter in place. Please understand we have an armed and dangerous person(s) still at large and police actively pursuing every lead in this active emergency event. Please be patient and use common sense until this person(s) are apprehended. We will continue to update the public with more information as it becomes available. All MBTA service remains suspended at this time."

• AT THE WHITE HOUSE: President Obama was briefed - and apparently called in the middle of the night - about developments in Boston, ABC's JONATHAN KARL reports. A White House official tells ABC News: "The President continued to be briefed overnight by Assistant to the President for Homeland Security and Counterterrorism Lisa Monaco about developments in the investigation as well as the events in Boston and Watertown, MA."

WHAT WE'RE WATCHING

-BOSTON SHOOTOUT ADDS TO INTENSE WEEK FOR WHITE HOUSE: ABC's Chief White House Correspondent Jonathan Karl discussed sleepless nights for President Obama and his national security team on "Good Morning America" today. WATCH: http://abcn.ws/10mXkAe

-BOMBING SUSPECTS 'THERE TO FIGHT': ABC News analyst, ex-FBI agent Brad Garrett, discusses the suspects in the Boston bombing. WATCH: http://abcn.ws/15raZXT

-EYEWITNESS ON 'LOUD, RAPID-FIRE' SHOOTOUT: Jeff Brayor says the first suspect was apprehended 15 feet from his front door. WATCH: http://abcn.ws/Z4wJWz

WHAT WE'RE READING

"BOSTON BOMB VICTIM IN ICONIC PHOTO HELPED IDENTIFY SUSPECTS," by Bloomberg's Asjylyn Loder & Esmé E. Deprez. Minutes before the bombs blew up in Boston, Jeff Bauman looked into the eyes of the man who tried to kill him. Just before 3 p.m. on April 15, Bauman was waiting among the crowd for his girlfriend to cross the finish line at the Boston Marathon. A man wearing a cap, sunglasses and a black jacket over a hooded sweatshirt looked at Jeff, 27, and dropped a bag at his feet, his brother, Chris Bauman, said in an interview. Two and a half minutes later, the bag exploded, tearing Jeff's legs apart. A picture of him in a wheelchair, bloodied and ashen, was broadcast around the world as he was rushed to Boston Medical Center. He lost both legs below the knee. 'He woke up under so much drugs, asked for a paper and pen and wrote, 'bag, saw the guy, looked right at me,' Chris Bauman said yesterday in an interview. Those words may have helped crack the mystery of who perpetrated one of the highest-profile acts of terror in the U.S. since the 2001 assault on New York City and the Washington area, one that killed three people and wounded scores." http://bloom.bg/ZB4g6u

IN OTHER NEWS

OBAMA ASSURES BOSTON IT 'WILL RUN AGAIN' AND 'FINISH THE RACE.' In Boston yesterday, President Obama acknowledged the devastation that had befallen the victims and their families but assured a church gathering that the city "will run again," reports ABC's MARY BRUCE. "We may be momentarily knocked off our feet, but we'll pick ourselves up," Obama told an audience at the Cathedral of the Holy Cross in Boston's South End during an interfaith service called "Healing Our City." "We'll keep going; we will finish the race." The cathedral was Obama's first stop, where he offered a message of hope. "Your resolve is the greatest rebuke to whoever committed this heinous act," the president told a crowd of dignitaries and families of the victims. "If they sought to intimidate us, to terrorize us, to shake us from those values that … make us who we are as Americans, well it should be pretty clear by now that they picked the wrong city to do it," at which point many attendees jumped to their feet. http://abcn.ws/XKFiEa

KERRY TO CONGRESS: 'MY HEART AND HEAD ARE IN BOSTON. Secretary of State John Kerry spent yesterday in Washington testifying before the Senate Foreign Relations and Appropriations Committees about next year's State Department budget. But, as ABC's DANA HUGHES reports, it was clear that the Boston Marathon attack was first and foremost on his mind. Similar to his emotional remarks yesterday in front of the House committees, the former senator from Massachusetts began his prepared testimony reflecting on his home state and the people of Boston. "It is no secret that my heart and my head are in Boston today with the president, with the families, with a lot of friends. There is a memorial service there, and I'm grateful to the president for going up there. I wish I could be there with him, but I need to be here and I understand that and I respect the needs to continue," Kerry told the Senate Foreign Affairs Committee on Thursday morning. He praised the president's speech in his testimony before the appropriations committee on Thursday afternoon. "I thought he was magnificent, gave a great, great speech, touched the hearts of everybody and captured Boston," said Kerry. http://abcn.ws/YycITO

KERRY: 'WE LOST A CITIZEN OF ANOTHER COUNTRY': Secretary Kerry yesterday also remarked on the global nature of the attack, expressing his condolences for the families of the victims who were killed and singling out the death of Lingzi LuI, the Boston University graduate student from China, a country Kerry just visited a few days ago. "We lost a citizen of another country, a young Chinese girl studying in Boston, a graduate student, who went there with her friends to watch the marathon and take part in this fabulous Patriot's Day rite that if nobody's ever experienced it … they'll be back, and there will be a bigger, better one next year," he said. "And we'll celebrate that spirit."

HARRY REID HITS 'PAUSE' ON GUN BACKGROUND CHECK BILL. Senate Majority Leader Harry Reid said yesterday that it was time to take a breath and regroup in the wake of a sweeping defeat on gun legislation this week, ABC's JEFF ZELENY reports. "I've spoken with the president," Reid said on the Senate floor. "He and I agree that the best way to keep working towards passing a background check bill is to hit a pause and freeze the background check bill where it is." He added: "We're going to come back to this bill." It remains an open question when, how and whether the White House and Reid can rally more support for the gun legislation. But Reid took the bill off the floor - a legislative maneuver - intended to keep his options alive. http://abcn.ws/11iAUwJ

BOEHNER UNCOMMITTED TO GUN VOTES IN HOUSE. After the U.S. Senate voted down a slate of proposals to toughen the country's gun laws Wednesday, House Speaker John Boehner yesterday was non-committal on the prospect of considering similar measures in the House of Representatives, notes ABC's JOHN PARKINSON. Still, the speaker maintained that the Republican-controlled committees of jurisdiction in the House will continue examining mental health and gun violence. "Our committees continue to work at this," Boehner, R-Ohio, said. "No decision has been made beyond that." When he was asked whether he will expedite consideration of a bill or follow regular order, in which a bill starts at the committee level, and, separately, whether he believes there should be a political price to pay for lawmakers who oppose stronger gun legislation, the speaker's tone carried a lack of urgency. "Our committees are going to continue to look at the violence in our society and look at these tragedies and determine whether there are common-sense steps that we can take to reduce the chances of this," Boehner said. "The relevant committees are working on this issue. I'm going to continue to work with them, and when we have a decision to announce, we'll announce it." http://abcn.ws/ZAkSez

LAHOOD: SEQUESTER CUTS MEAN UP TO 2 HOUR FLIGHT DELAYS. Leaving on a jet plane any time after Sunday? Better get ready to sit tight, notes ABC's FREDA KAHEN-KASHI and SARAH PARNASS. Department of Transportation Secretary Ray LaHood announced Thursday that flight delays at major airports could reach up to two hours and 10 minutes - and that's without accounting for weather delays or technical malfunctions. The drawn-out delays are a side effect of sequestration, and if they come to pass as predicted, they will be one of the most highly visible effects so far. The Federal Aviation Administration begins furloughing 47,000 employees on Sunday, April 21, and passengers may start seeing delays as early as next week. Delays are expected to peak in the summer months due to travel and weather. The DOT is required to cut $1 billion from its budget, thanks to the sequester. Of that, $637,000 will come from the FAA. Employees will be required to take 11 days of unpaid leave between Sunday and the end of September. LaHood couldn't give more details, saying the scheduling of the furloughs within that time frame would be up to the individual airports. http://abcn.ws/10lCSj0

WHO'S TWEETING?

@Boston_Police: #WANTED: Suspect identified as 19 year-old Dzhokhar Tsarnaev of Cambridge. Suspect considered armed & dangerous. pic.twitter.com/jFdHLGsrGc

@GioBenitez: #Breaking: The FBI has just released a new photo of suspect #2 @ABC pic.twitter.com/Gdryq7HPkU

@rickklein: riveting! RT @WBUR: @hereandnowrobin interviewing her nephew, who went to Cambridge R&L with Dzhokhar Tsarnaev LISTEN http://wbur.fm/FPqGMz

@wbznewsradio: WBZ-TV's @PetesWire spoke to brothers' U.S.-based uncle, who says "just wish they never existed." Says brothers' family still in Russia.