Mombasa, Kenya (AP) - Undeterred Somali pirates went on a hijacking spree, brazenly capturing four more ships and taking over 60 crew members hostage in the Gulf of Aden, the waterway at the center of the world's fight against piracy.
Pirates have vowed to retaliate for five colleagues slain by U.S. and French forces in recent hostage rescues -- and the top U.S. military officer said Tuesday he takes those comments seriously.
But Adm. Michael Mullen, chairman of the Joint Chiefs of Staff, told ABC's "Good Morning America" that "we're very well prepared to deal with anything like that."
Despite Mullen's confident statement and President Barack Obama's warning of further U.S. action, pirates captured two more nautical trophies Tuesday to match the two ships they seized a day or two earlier.
The latest seizures were the Lebanese-owned cargo ship MV Sea Horse, the Greek-managed bulk carrier MV Irene E.M. and two Egyptian fishing boats. Maritime officials said the Irene carried 21 to 23 Filipino crew and Egyptian officials reported 36 fishermen, mostly Egyptians, on the two boats.
It was not known exactly how many crew the Sea Horse had on board, but a ship that size would probably need at least a dozen.
NATO spokeswoman Shona Lowe said pirates in three or four speedboats captured the Sea Horse on Tuesday -- an attack that came only hours after the Irene was seized in a rare overnight raid.
The two Egyptian fishing boats were hijacked in the gulf off Somalia's northern coast but it was not clear if those attacks came Monday or Sunday.
The Gulf of Aden, which links the Suez Canal and the Red Sea to the Indian Ocean, is one of the world's busiest and most vital shipping lanes, crossed by over 20,000 ships each year.
A flotilla of warships from nearly a dozen countries has patrolled the Gulf of Aden and nearby Indian Ocean waters for months. They have halted many attacks on ships this year, but say the area is so vast they can't stop all hijackings.
Pirates have attacked 78 ships this year, hijacking 19 of them, and 17 ships with over 300 crew still remain in pirates' hands, according to Noel Choong, who heads the International Maritime Bureau's piracy reporting center in Kuala Lumpur.
Each boat carries the potential of a million-dollar ransom.
The Irene, flagged in the Caribbean island nation of St. Vincent and the Grenadines, was sailing from the Middle East to South Asia, Choong said.
U.S. Navy Lt. Nathan Christensen, spokesman for the Bahrain-based 5th Fleet, said the Irene carried 23 Filipino crew, while Choong reported it had 21 and Greek marine officials said it carried 22. here was no immediate way to reconcile the figures.
A maritime security contractor, speaking on condition of anonymity because it is a sensitive security issue, said the Irene put out a distress signal "to say they had a suspicious vessel approaching. That rapidly turned into an attack and then a hijacking."
"They tried to call in support on the emergency channels, but they never got any response," the contractor said.
The latest seizures come after Navy SEAL snipers rescued American ship captain Richard Phillips on Sunday by killing three young pirates who held him captive in a drifting lifeboat for five days. A fourth pirate surrendered after seeking medical attention for a wound he received in trying to take over Phillips' vessel, the Maersk Alabama.
Phillips on Tuesday was aboard a Navy vessel at an undisclosed location, Christensen said. He was initially taken aboard the Norfolk, Va.-based USS Bainbridge and then flown to the San Diego-based USS Boxer for a medical exam.
In Washington, Obama appeared to move the piracy issue higher on his agenda, vowing the United States would work with nations around the world to fight the problem.
"I want to be very clear that we are resolved to halt the rise of piracy in that region and to achieve that goal, we're going to have to continue to work with our partners to prevent future attacks," Obama told reporters Monday.
The 19 crew members of the Alabama celebrated their skipper's freedom with beer and an evening barbecue Monday in the Kenyan port of Mombasa, said crewman Ken Quinn.
The vessel's chief mate was among those urging strong U.S. action against piracy.
"It's time for us to step in and put an end to this crisis," Shane Murphy said. "It's a crisis. Wake up."
The U.S. is considering new options to fight piracy, including adding Navy gunships along the Somali coastline and launching a campaign to disable pirate "mother ships," according to military officials. They spoke on condition of anonymity because no decisions have been made yet.
The four pirates who attacked the Alabama were between 17 and 19 years old, Defense Secretary Robert Gates said.
"Untrained teenagers with heavy weapons," Gates told students and faculty at the Marine Corps War College. "Everybody in the room knows the consequences of that."
U.S. officials were now considering whether to bring the fourth pirate, who surrendered shortly before the sniper shootings, to the United States or possibly turn him over to Kenya. Both piracy and hostage-taking carry life prison sentences under U.S. law.
The French navy late Monday handed over the bodies of two Somali pirates killed last week in a hostage rescue operation, and the bodies were buried in Somali's semiautonomous northern region of Puntland.
Associated Press writers who contributed to this report include Pauline Jelinek from Washington, Mohamed Olad Hassan in Mogadishu, Somalia; Michelle Faul, Malkhadir M. Muhumed, Tom Maliti and Todd Pitman in Kenya; Eileen Ng in Kuala Lumpur, Malaysia; Adam Schreck in Manama, Bahrain, Lara Jakes, Anne Gearan and Devlin Barrett in Washington; Slobodan Lekic in Brussels and John Curran in Burlington, Vermont.
The M.V. Irene E.M. was hijacked early Tuesday, but it was not immediately clear where the ship is based or who owns it. On Monday, Somali pirates also seized two Egyptian fishing boats in the Gulf of Aden off Somalia's northern coast, according to Egypt'