Five of the Somali pirates who released a hijacked, oil-laden Saudi supertanker drowned with their share of a reported $3m (£1.96m) ransom after their small boat capsized, local sources said today.

A pirate who was not part of the pirate operation but knew those involved, Daud Nure, said the boat with eight people on board overturned in a storm after dozens of pirates left the Sirius Star, following a two-month standoff in the Gulf of Aden, that ended yesterday.

He said five people died and three people reached the shore after swimming for several hours.

Jamal Abdulle, a resident of the Somali coastal town of Haradhere, close to where the ship was anchored, also confirmed that the boat sank and that the portion of the ransom money that had been shared between dozens of pirates was lost.

The Saudi owners of the ship, Vela International, today confirmed that the vessel and crew had been released.

Among the frees hostages were two British crewmen, chief engineer Peter French, from County Durham, and James Grady, from Renfrewshire.

US navy photos showed a parachute, carrying what they described as "an apparent payment", floating towards the tanker.

Vela's president, Saleh K'aki, said: "We are very relieved to know that all the crew members are safe and I am glad to say that they are all in good health and high spirits.

"This has been a very trying time for them and certainly for their families. We are very happy to report to their families that they will be on their way home soon."

The Sirius Star and its 25-member crew had been held since 15 November. Its cargo of crude oil was valued at $100m at the time. The capture was seen as a dramatic demonstration of the pirates' ability to strike high-value targets hundreds of miles offshore.

On the same day the Saudi ship was freed, pirates released a captured Iranian-chartered cargo ship, Iran's state television reported today. It said the ship, Daylight, was carrying 36 tonnes of wheat when it was attacked in the Gulf of Aden on 18 November and seized by pirates. All 25 crew are in good health and the vessel is sailing towards Iran, the TV report said.

The US navy announced this week it will head a new anti-piracy taskforce after more than 100 ships were attacked last year. Nato and the European Union already have warships patrolling the Gulf of Aden and have intervened to prevent several ships from being captured.

More than a dozen ships with about 300 crew members are still being held by pirates off the coast of Somalia, including the weapons-laden Ukrainian cargo ship, MV Faina, which was seized in September.

The multimillion dollar ransoms are one of the few ways to earn a living in the impoverished, war-ravaged country. Somalia has not had a functioning government since 1991 and nearly half of its population depends on aid.