The captain of a U.S.-flagged ship held hostage by armed pirates on a lifeboat in the Indian Ocean appears to be alive after a daring escape attempt -- but the pirates now seem to have fuel and to be moving closer to shore, sources told ABC News.
The latest evidence that Capt. Richard Phillips, 53, is alive came as the pirates holding him in a covered lifeboat fired shots at U.S. Navy sailors who approached their vessel at an undisclosed time after the escape bid.
The Navy asked for a show of life and received it, the source said, though it was not clear what the Navy was shown.
The Navy ultimately withdrew from the confrontation.
The U.S. military has also spoken to Phillips since he jumped from the lifeboat in an attempt to escape the pirates holding him early Friday, a U.S. official told ABC News. That official would not comment on Phillips' condition, saying only that "he's still alive."
Sources added that, contrary to earlier news reports, the pirates had fuel on the lifeboat and had used it to move within 20 miles off the African coast.
Crewman: 'He Saved Our Lives'
The latest developments at sea came as Phillips' freighter, the Maersk Alabama, pulled into port in Mombasa, Kenya, Saturday evening local time with its crew members waving and pumping their fists.
The 17,000-ton ship, with 19 crew members onboard, was flanked by escort boats and helicopters flying overhead.
Several of the crew members said the captain had saved their lives. When asked how, one said he'd traded himself for the safety of the crew.
"He saved our lives!" second mate Ken Quinn, of Bradenton, Fla., declared after he walked off the ship, according to The Associated Press. "He's a hero!"
One crew member said his friend stabbed a pirate with his knife. As he told the story, his friend, a crew member, showed off his knife.
A crew member flashed a thumbs up sign and one said he was looking forward to having a beer. Some crew members wore bulletproof vests.
The last time Phillips was known to have been seen was by an unmanned Scan Eagle drone early Friday as he jumped from the lifeboat into the Indian Ocean and attempted to swim away. The lifeboat also was being watched by a U.S. warship off the coast of Africa.
The pirates quickly appeared and began firing their weapons. One jumped into the water and dragged the captain back to the boat, where he was seen being bound by his captors.
Earlier, the pirates had put the captain on a radio line with the USS Bainbridge, but they refused to do so initially after his attempted escape, and his condition was unknown.
Though the Pentagon is directing the military response to the crisis, President Obama is getting personally involved.
A White House group on piracy met throughout the day Saturday. The administration is keeping all options on the table, including direct military action to free the captain, the first American taken by pirates since 1804.
Maersk Line CEO: 'Ship Is a Crime Scene'
Today, with the Maersk Alabama's crew in port, the head of the ship's parent company, Maersk Line Ltd., said that though all attempts are being made to make them comfortable, they must to stay aboard the vessel until the FBI completes an investigation of the piracy incident.
"This ship is a crime scene," Maersk President and CEO John Reinhart told the media in Norfolk, Va. "Therefore, we have to let the FBI begin the process to investigate the crime of the pirate attack."
The FBI's plans to interview the crew members could indicate the Justice Department will prosecute the pirates since they attacked a U.S.-flagged vessel.
Maersk also announced today it had set up an e-mail address "where concerned persons from around the world may send messages of support for the captain, crew and families of the Maersk Alabama."
People were invited to send their thoughts to email@example.com.
"We would like to recognize all the expressions of support received already," the company said as it disclosed the e-mail address Saturday.
Standoff in the Indian Ocean
With reinforcements on the way and other pirated ships heading to the scene to attempt to take Phillips and his captors to Somalia, the U.S. Navy is bracing for a confrontation on the high seas.
The Navy's objective is to stop the lifeboat from linking up with pirate mother ships or heading ashore without using force.
On Saturday, one of the pirate ships that had been heading to the scene, a German vessel with 24 hostages on board, turned around. It couldn't find the lifeboat.
Meanwhile, inside the lifeboat, Phillips and his captors -- four pirates armed with AK-47 rifles -- likely face brutal conditions.
"It's hot. It's uncomfortable," Adm. Richard Gurnon said. "These bob like a cork. They don't ride very well. There are four pirates with him. It's the Indian Ocean. And it's 100 degrees."
Phillips and four pirates have been in the lifeboat for four days. It can hold 76 people, so there is room for them to move around.
The Bainbridge has been keeping an eye on the four pirates in recent days and has been joined by other U.S. warships -- the Halyburton, which carries two helicopters and the USS Boxer, which carries about 20 helicopters and attack planes.
Back in Phillips' hometown of Underhill, Vt., the captain's wife, Andrea, has helped put up yellow ribbons, but has remained silent about her husband's plight. She issued a statement Friday through Maersk thanking neighbors and the nation for its outpouring of support.
"We have felt the compassion of the world through your concern for Richard. My husband is a strong man and we will remain strong for him. We ask that you do the same," Andrea Phillips said.
High-Seas Drama: The Standoff Begins
The high-seas drama settled into a standoff after the pirates boarded the container ship Maersk Alabama Wednesday while firing AK-47 assault rifles, but were forced off the ship a short time later by the unarmed American crew, which captured one of the pirates.
Phillips apparently prevented a bloody counterattack by the pirates by offering himself as a hostage. A prisoner exchange was arranged, but the pirates didn't keep their part of the bargain and refused to let the captain go free
After the escape bid on Friday, the pirates threatened to kill him Phillips the U.S. Navy attempted to rescue him.
The Maersk Alabama was in Somali waters because it was carrying food aid to hungry people in Africa, including Somalia.
ABC News' Martha Raddatz, Jason Ryan and Anne Marie Dorning contributed to this report.