Congress Set to Reconvene

Congress is set to reconvene today after its leaders and President Bush assured the world that America would withstand the worst terrorist attacks the nation has ever suffered.

Stern and somber, the president addressed the nation from the Oval Office Tuesday when countless people died after hijacked planes were flown into the World Trade Center towers in New York and the Pentagon in Northern Virginia. A fourth plane that was presumed to have been hijacked crashed in western Pennsylvania.

Ominous Warning

In an ominous warning to nations where suspected terrorists may be residing, Bush promised that those responsible for the attacks and "those who harbor them" would be found and punished.

"The pictures of airplanes flying into buildings, fires burning, huge structures collapsing have filled us with disbelief, terrible sadness and a quiet, unyielding anger," Bush said."These acts of mass murder were intended to frighten our nation into chaos and retreat. But they have failed."

The hunt for terrorists is under way. Sen. Orrin Hatch, R-Utah, and other lawmakers who have been briefed by intelligence officials told ABCNEWS that all signs point to the involvement of Osama bin Laden, who is already indicted on charges he organized the 1993 bombings of two U.S. embassies in Africa.

Law enforcement sources say the FBI has begun to issue search warrants on U.S. residents based on information gleaned from passenger manifests of the planes. Agents also have learned the exact seat of one hijacker from a flight attendant who managed to dial 911 before her plane crashed.

Pentagon in Flames

Late into Tuesday evening, firefighters were still trying to douse flames that when the Pentagon was slammed by a hijacked American Airlines Flight 77. The fire chief in Arlington, Va., estimated 100 to 800 were killed at the site.

The plane penetrated deep into the five-sided building, sparking an inferno and prompting an enormous rescue operation. Hospitals in Northern Virginia scrambled to treat dozens of casualties from the Pentagon as the building continued to burn into the late afternoon. Air Force F-16s circled in the sky as rescue crews worked the scene.

Among those killed in the attack was Flight 77 passenger Barbara Olson, a former federal prosecutor and the wife of U.S. Solicitor General Theodore Olson.

Despite the chaos, Defense Secretary Donald Rumsfeld pledged to reopen the Pentagon today.

A Show of Support and Unity

In wake of the attacks Tuesday, leaders of both the Senate and the House were taken to a secure location where they met to plot strategy to deal with the tragedies. They returned to Capitol Hill Tuesday to inspire unity in the nation.

Dozens of lawmakers then gathered for an emotional event on the Capitol steps, singing "God Bless America" and hugging one another following statements by their congressional leaders.

Determined to show the attacks would not halt the U.S. government, Senate Majority Leader Tom Daschle, D-S.D., declared Congress would get back to work immediately today.

"As the representatives of the people, we are here to declare that our resolve has not been weakened by these horrific and cowardly acts," Daschle said.

ABCNEWS' Brian Hartman and Aditya Raval contributed to this report.