The militants say they had 'promised' Bin Laden to kill Americans

Al-Qaeda suspect Fawaz al-Rabeei, who had "pledged" to kill Americans, was originally given a 10-year jail term for killing a Yemeni policeman.

The judges upheld another death sentence and raised from 10 to 15 years the jail terms for two of the suspects.

One member of the tanker Limburg's crew died in the attack in October 2002.

The tanker was carrying 400,000 barrels of crude oil when a blast ignited a fire on board badly damaging it and spilling 90,000 barrels of oil into the Gulf of Aden.

'God is Great!'

The court in Sanaa upheld jail terms ranging from three to 10 years for the other suspects on other activities, including a plot to kill the US ambassador to Yemen and attacks on Western embassies.

One of the men was found guilty of involvement in an attack on a helicopter carrying Texas-based Hunt Oil employees and detonating explosives at a civil aviation authority building.

We had given our pledge to Sheikh Osama [Bin Laden] to kill Americans Fawaz al-Rabeei

"God is great, there is no god but God and America is the enemy of God," the men shouted after sentencing.

"[We] were very close to Sheikh Osama Bin Laden... We had given our pledge to Sheikh Osama to kill Americans," Rabeei said in his final statement to the court in December, Reuters news agency reported.

It was not clear if the men would go to Yemen's High Court, which can overturn the rulings.