An American warship, the USS Bainbridge, has reached the area off the coast of Somalia where a cargo ship was seized by pirates a day earlier.US crew members have recaptured their ship but the captain is still being held hostage by the attackers.The pirates' boat is floating near the Maersk Alabama, its owners told the Associated Press. At least six other vessels are said to be heading its way.The ship was taken about 500km (311 miles) off Somalia's coast.US Secretary of State Hillary Clinton said the government was following the situation very closely and urged the world to act to end the "scourge" of piracy.'Ransom'Earlier, US media organisations telephoned members of the ship's crew to get details of their struggle against the pirates.Second mate Ken Quinn told US TV network CNN how the crew had captured one of the pirates and kept him tied up for 12 hours.As they attempted to negotiate the release of their captain, who has been named as Richard Phillips, they freed the captive pirate.But the gang refused to free Capt Phillips."Right now they want to hold our captain for ransom, and we are trying to get him back," second mate Quinn told CNN."So now we're just trying to offer them whatever we can - food. But it's not working too good."He said the attackers had fled in a lifeboat and crew members were using radios to keep in contact with Capt Phillips.Family members said Capt Phillips had offered himself to the pirates to secure the safety of his crew."What I understand is that he offered himself as the hostage," Gina Coggio, his wife's half-sister, told the AP news agency. "That is what he would do. It's just who he is and his response as a captain."In a statement issued on Wednesday, the ship's owners, Maersk, confirmed much of second mate Quinn's account."The armed hijackers who boarded this ship earlier today have departed, however they are currently holding one member of the ship's crew as a hostage," Maersk said."The other members of the crew are safe and no injuries have been reported."Surge in hijackingsThe ship was first attacked by several pirate boats in the early hours of Wednesday.It is not clear how many attackers were involved, but accounts from the sailors on the Maersk Alabama suggest that four boarded the vessel.Maritime officials said the ship had taken all possible evasive action before it reported that the pirates had boarded.Pirate attacks have been increasing rapidly in recent years - more than 130 incidents were reported in 2008, including almost 50 successful hijacks.Pirates typically hold the ships and crews until large ransoms are paid by the shipping companies - last year the firms handed over about $80m (£54m).After a lull earlier this year, this was the sixth ship seized off Somalia in the past week.The attacks are threatening to destabilise one of the world's busiest shipping lanes.Source: BBC