A pirate gang that staged an abortive attack on a second US ship loaded with food aid said Wednesday it was singling out American vessels and would kill their crews. French forces detained 11 other hijackers in a high-seas raid. Pirates fired grenades and automatic weapons at the cargo ship 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 US Navy guard. A pirate whose gang attacked the ship said 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 US Navy sharpshooters killed three pirates Sunday to win the release of a hijacked American sea captain, Richard Phillips of the Maersk Alabama. Secretary of State Hillary Rodham Clinton said the US will pursue new efforts to track down and freeze the assets of pirates, who have reaped multimillion-dollar ransoms for ships they have captured. "We may be dealing with a 17th century crime, but we need to bring 21st century solutions to bear," she said at a news conference in Washington. Clinton said the Obama administration also would call for immediate meetings of an international counter-piracy task force to expand naval coordination against pirates operating in the key shipping lanes off Somalia. French forces 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 serving in the international fleet trying to protect shipping in the Gulf of Aden. France has traditionally been aggressive in fighting piracy - this was its ninth military operation against pirates. Three Somali pirates were in the French city of Rennes on Wednesday facing judicial investigation after being captured in a hostage rescue Friday. Several other pirates are also in French custody after being seized last year. 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. 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 UN World Food Program. It warded off the pirates with evasive maneuvers, said US 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 US 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 US hostage rescues, brigands have seized four vessels and more than 75 hostages since Sunday's dramatic rescue of Phillips. Pirates released a Greek-owned cargo ship Wednesday and Greek authorities said all 24 crewmen on the Titan were in good health. The ship had been hijacked March 19 in the Gulf of Aden. In all, Somali pirates are holding over 280 sailors on 15 ships - at least 76 of those sailors captured in the last few days. Pirates have attacked 79 ships this year and hijacked 19 of them, according to the International Maritime Bureau, a piracy watchdog. Pirates can extort $1 million or more for each ship and crew seized off the Horn of Africa - and Kenya estimates they raked in $150 million last year. The United States has asked the International Red Cross and Somali officials to help locate the families of the three pirates slain Sunday by Navy snipers so their remains can be returned, a senior US official said on condition of anonymity because he was not authorized to speak on the record. The difficulties in getting food aid delivered could leave some Somalis hungry. World Food Program spokesman Peter Smerdon said more food aid was to have been delivered by another cargo ship hijacked Tuesday, the Lebanese-owned MV Sea Horse. It was headed to Mumbai, India, to pick up 7,327 tons of WFP food for Somalia. "WFP is also extremely concerned that people in Somalia will go hungry unless the Sea Horse is quickly released or a replacement ship can be found," he said. Hours before the attack on the Sea Horse, pirates seized the Greek-managed bulk carrier MV Irene E.M. in an unusual nighttime raid. They also captured two Egyptian fishing trawlers carrying 36 fishermen. Pirates say they are fighting illegal fishing and dumping of toxic waste in Somali waters but now operate hundreds of miles from there in a sprawling 1.1 million square-mile danger zone. 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. More than 20,000 ships cross the vital sea lane every year. Pirate attacks in the region have rapidly increased lately, according to the International Maritime Bureau. In less than four months this year, there have been 79 attacks, compared to 111 for all of 2008. In 2003, there were only 21 attacks by Somalis in this expanse of water. Last year pirates took 815 sailors hostage and hijacked 42 ships.