US President George W Bush has opposed a move by Congress to label the Ottoman massacres of Armenians a genocide saying it would do 'great harm' to ties with key ally Turkey.

'I urge members to oppose the Armenian genocide resolution now being considered by the House Foreign Affairs Committee,' Mr Bush said.

Earlier today, US Secretary of State Condoleezza Rice said if the resolution were passed it would be 'very problematic' for ties with Turkey and for Middle East peace.

Ms Rice also said the House of Representatives resolution would be 'very destabilizing for our efforts in Iraq and Afghanistan'.

Ms Rice said she sympathized with the Armenians' fate during World War I, when 1.5m died in systematic deportations and killings under the Ottoman Empire.

Turkey has warned that if the resolution is passed it could force Ankara to bar the US from a key military base in its south and Secretary of Defence Robert Gates noted that about 70% of all US air cargo going into Iraq goes through Turkey.

Mr Bush said: 'We all deeply regret the tragic suffering of the Armenian people.

'This resolution is not the right response to these historic mass killings. Its passage would do great harm to our relations with a key ally in NATO and in the global war on terror.'

Rejecting the genocide label, Turkey argues that 250,000 to 500,000 Armenians and at least as many Turks died in civil strife when Armenians took up arms for independence in eastern Anatolia during World War I.