Pirates fired grenades and automatic weapons at the Liberty Sun, but its American crew successfully blockaded themselves inside the engine room. The ship was damaged in Tuesday's attack but escaped and was heading to Kenya under U.S. Navy guard.
A pirate whose gang attacked the aid ship admitted Wednesday that his group was targeting American ships and sailors.
"We will seek out the Americans and if we capture them we will slaughter them," said a 25-year-old pirate based in the Somali port of Harardhere who gave only his first name, Ismail.
"We will target their ships because we know their flags. Last night, an American-flagged ship escaped us by a whisker. We have showered them with rocket-propelled grenades," boasted Ismail, who did not take part in the attack on the Liberty Sun.
The move comes after U.S. Navy sharpshooters killed three pirates Sunday to win the release of a hijacked American sea captain, Richard Phillips of the Maersk Alabama.
The French forces, meanwhile, launched an early morning attack on a pirate ship after spotting it Tuesday with a surveillance helicopter and observing the pirates overnight. The raid thwarted the bandits' planned attack on the Liberian cargo ship Safmarine Asia, the French Defense Ministry said.
The statement called the pirate vessel a "mother ship" — usually a seized foreign ship that pirates use to transport speedboats far out to sea and resupply them. The ship was intercepted 550 miles (900 kilometers) east of the Kenyan city of Mombasa.
The 11 detained pirates were being held on the Nivose, a French frigate among the international fleet trying to protect shipping in the Gulf of Aden. France already is holding several pirates for prosecution.
Tuesday's attack on the Liberty Sun foiled the reunion between Phillips and the 19-man crew he saved with his heroism. Phillips had planned to meet his crew in Mombasa and fly home with them Wednesday, but was stuck on the USS Bainbridge when it was diverted to help the Liberty Sun.
U.S. Cargo Ship Evades Somali Pirate AttackMaersk Crew Heads Home, Will Reunite With Captain in U.S. The crew left without him, flying to Andrews Air Force base in Maryland in a chartered plane.
"We are very happy to be going home," crewman William Rios of New York City said before departing Wednesday. "(But) we are disappointed to not be reuniting with the captain in Mombasa. He is a very brave man."
Third mate Colin Wright, from Galveston, Texas told ABC's "Good Morning America" that fighting off pirates gave him a new appreciation for life.
"I'll just love to hug my mother," Wright said. "Everybody out there give your mother a hug. Yeah, don't wait. Life is precious. And what a beautiful world."
The Liberty Sun had left Houston with a crew of 20 American sailors and a load of aid for the U.N. World Food Program. It warded off the pirates with evasive maneuvers, according to U.S. Navy Lt. Nathan Christensen of the Bahrain-based 5th Fleet.
"We are under attack by pirates, we are being hit by rockets. Also bullets," Liberty Sun crewman Thomas Urbik, 26, wrote his mother in an e-mail. "We are barricaded in the engine room and so far no one is hurt. (A) rocket penetrated the bulkhead but the hole is small. Small fire, too, but put out."
By the time the Bainbridge arrived five hours later, the pirates had left. A small group of armed U.S. sailors from the Bainbridge went aboard the Liberty Sun to ensure its safe journey to Mombasa.
Despite President Barack Obama's vow to take action against the rise in banditry and the deaths of five pirates in French and U.S. hostage rescues, brigands have seized four vessels and more than 75 hostages since Sunday's dramatic rescue of Phillips.
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