The crew of a US ship attacked off Somalia have called on President Barack Obama to lead the battle against piracy. The call came after US Navy snipers shot dead three Somali pirates who had been holding Captain Richard Phillips hostage in a drifting lifeboat circled by US warships for five days. A fourth raider was taken prisoner. More than 250 hostages of many nationalities are still being held along the Somali coast by pirates who have seized dozens of vessels, from tankers to yachts, in recent months. Mr Phillips, the captain of the US-flagged Maersk Alabama container ship, was the first American seized by pirates who have plundered ships in the Gulf of Aden and Indian Ocean for years. The US Navy said officers took a split-second decision to shoot his kidnappers because they were pointing their AK-47 rifles at him. Mr Obama had given commanders standing authority to use appropriate force to free Mr Phillips. The Maersk Alabama's first nautical officer Shane Murphy said: "America has to be in the forefront to put an end to this crisis. This crew was lucky to be out of it with everyone alive. We are not going to be that lucky again." Mr Obama said: "We must continue to work with our partners to prevent future attacks, be prepared to interdict acts of piracy and ensure that those who commit acts of piracy are held accountable for their crimes." Somali pirates vowed to avenge the shootings of their comrades, as well as a French military assault to rescue a yacht on Friday in which two pirates were killed and three captured. A pirate called Hussein warned: "The French and the Americans will regret starting this killing. We do not kill, but take only ransom. We shall do something to anyone we see as French or American from now." The Maersk Alabama, carrying food aid for Somalis, was attacked far out in the Indian Ocean on Wednesday, but its 20 American crew regained control. Phillips volunteered to go with the pirates in a lifeboat in exchange for the crew's safety.