Pirates holding a Japanese chemical tanker off the northeastern coast of Somalia are demanding a million-dollar ransom or they threatened to kill its crew members, the United Nations said on Monday.
The Golden Nori, carrying tens of thousands of tonnes of inflammable benzene, was hijacked on October 28 along with 23 crew members from Myanmar, the Philippines and South Korea.
"The pirates are asking for one million US dollars as ransom, whilst Puntland authorities are asking the pirates to surrender peacefully to the Puntland coast," the UN Office for the Coordination of Humanitarian Affairs (OCHA) said in a statement.
The pirates "are threatening to kill them if ransom is not paid," the statement said.
Authorities in Puntland, a Somali semi-autonomous region, who are negotiating with the pirates have sent militia to Bosaso harbour, a few nautical miles from where the vessel is held.
Meanwhile two US Navy ships are blocking supplies to the tanker, which was sailing from Singapore to Israel when it was hijacked, in a bid to to force the pirates to abandon the vessel.
The Golden Nori is the last vessel remaining under pirates' control off the Somali coastline after the Comoran-flagged cargo MV Al Marjan was released a fortnight ago.
A US-led multilateral taskforce is conducting counter-piracy operations off the volatile Horn of Africa.
Rampant piracy off Somalia stopped briefly during the strict rule of an Islamist movement in the second half of 2006, but resumed after Ethiopian and Somali government troops ousted the Islamists at the end of 2006.
Numerous attacks have occurred this year off Somalia's 3,700 kilometre (2,300 mile) coastline, prompting the International Maritime Bureau to advise sailors to steer clear.
Somalia lies at the mouth of the Red Sea on a major trade route between Asia and Europe via the Suez canal. It has not had a functional government since the 1991 ouster of dictator Mohamed Siad Barre.