The US is monitoring "very closely" a container ship hijacked by pirates off Somalia's coast, Hillary Clinton, the US secretary of state, has said, amid confusion over the fate of the vessel and its American crew.
The Pentagon said on Thursday that it was seeking a peaceful solution to the incident, but warned that no option had been ruled out.
The pirates boarded the 17,000 tonne Danish-owned Maersk Alabama about 450km off the coast of Somalia on Wednesday and briefly seized control before apparently being repelled by the ship's 20-strong crew.
However the pirates are still reportedly holding the US captain hostage in a separate small boat, which Clinton said had apparently run out of fuel.
US media reports quoted the father of a crew member on Thursday as saying the ship was heading to a Kenyan port with an armed guard after a US Navy team boarded the ship, but this could not be confirmed.
Officials from the US Federal Bureau of Investigation (FBI) also said on Thursday they had assigned negotiators to help secure the release of the ship's captain.
Warship sent
Earlier on Thursday, the US Navy warship Bainbridge arrived on the scene and was near the 17,000-tonne Maersk Alabama as crew members negotiated with the pirates for the return of the captain.
Half a dozen other ships that had been patrolling the area, but were hours away when the hijacking occurred, were heading to the scene.
The hijacking was the first involving an American crew off the Horn of Africa.
Kevin Speers, a spokesman for Maersk Line, the US subsidiary of Denmark's AP Moller-Maersk which owns the ship, confirmed that the crew had regained control of the Maersk Alabama after the pirates left the ship with the captain.
He added that the crew were unharmed.
Colin Wright, who identified himself as the third mate on the ship, told the Associated Press news agency by satellite phone that the crew were also trying to negotiate the hostage's release.
Among the ship's cargo are 400 containers of food aid, including 232 containers belonging to the UN World Food Programme that were destined for Somalia and Uganda.
Attacks resume
The Maersk Alabama hijacking comes just days after armed men took control of a British-owned ship and after three other ships were seized over the weekend.
There had been a relative lull in the number of hijackings in the first three months of 2009, with eight ships overrun by pirates in the Gulf of Aden, a major shipping route between the southern and northern hemispheres.
Somali pirates last year seized dozens of vessels close to the Somali coastline in their attempt to secure ransom payments, taking hundreds of sailors hostage.
The drop in the number of successful pirate attacks in the past three months was largely due to the increased presence of foreign navies in the area.