Mombasa, Kenya ? Somali pirates were back to business as usual Tuesday, defiantly seizing four more ships with 60 hostages after U.S. sharpshooters rescued an American freighter captain. “No one can deter us,” one bandit boasted.

The freed skipper, Richard Phillips, will return home to the United States today, after reuniting with his 19-man crew in the Kenyan port of Mombasa, according to the shipping company Maersk Line Ltd.

The brigands grabbed more ships and hostages to show they would not be intimidated by President Barack Obama’s pledge to confront the high-seas bandits, according to a pirate based in the Somali coastal town of Harardhere.

“Our latest hijackings are meant to show that no one can deter us from protecting our waters from the enemy because we believe in dying for our land,” Omar Dahir Idle told The Associated Press by telephone. “Our guns do not fire water. I am sure we will avenge.”

On Monday, Obama vowed to “halt the rise of piracy” without saying exactly how the U.S. and allies would do it.

The pirates have vowed vengeance for five colleagues slain by U.S. and French forces in two hostage rescues since Friday.

“The recent American operation, French navy attack on our colleagues or any other operation mean nothing to us,” said Idle, 26, whose gang holds a German freighter with 24 hostages.

The pirates say they are fighting illegal fishing and dumping of toxic waste in Somali waters but have come to operate hundreds of miles from there in a sprawling 1.1 million square-mile danger zone.

The top U.S. military officer, Adm. Michael Mullen, said he takes the pirates’ threats seriously, but “we’re very well prepared to deal with anything like that.” Mullen, chairman of the Joint Chiefs of Staff, spoke on ABC’s “Good Morning America.”

After a lull at the beginning of the year because of rough seas, the pirates since the end of February have attacked 78 ships, hijacked 19 of them and hold 16 vessels with more than 300 hostages from a dozen or so countries.

Pirates can extort $1 million and more for each ship and crew. Kenya estimates they raked in $150 million last 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 but say the area is so vast they can’t stop all hijackings.

The Gulf of Aden, which links the Suez Canal and the Red Sea to the Indian Ocean, is the shortest route from Asia to Europe and one of the world’s busiest shipping lanes, crossed by more than 20,000 ships each year. The alternative route around the continent’s southern Cape of Good Hope takes up to two weeks longer at huge expense.

The U.N. envoy to Somalia called piracy a “pandemic” and urged the bandits’ financial backers to be identified quickly and held accountable.

Ahmedou Ould-Abdallah praised the action by Washington and Paris, calling it “a strong message” to the pirates and their backers.

Phillips, 53, of Underhill, Vt., was steaming Tuesday toward Kenya aboard the USS Bainbridge, where he is being debriefed by FBI officials and maritime experts, said a senior U.S. defense official in Washington. He said the investigators are gathering evidence of what each captor did for possible criminal investigations and to better prepare for future hostage situations. The official spoke on condition of anonymity because he was not authorized to speak on the record.

Phillips will take a chartered flight to meet his family at Andrews Air Force Base, Md., for a private reception, according to Maersk. He was rescued Sunday when U.S. Navy SEALs snipers killed three pirates holding him hostage on a lifeboat, and a fourth surrendered. Phillips had been held captive for five days after exchanging himself to safeguard his crew during a thwarted hijacking of the Alabama by the pirates last week.