A U.S. House committee on Wednesday defied President George W. Bush by passing a resolution calling the 1915 massacre of Armenians genocide, a step the White House warns could damage U.S. goals in the Middle East.

The measure, passed by the House Foreign Affairs Committee by a 27-21 margin,will be sent to the House floor, where Democratic leaders say there will be a vote within weeks.

Turkey, a key NATO ally that has supported U.S. efforts in Iraq, has strongly opposed the measure and warned it could damage relations between the two countries.

At issue is the killing of as many as 1.5 million Armenians by Ottoman Turks around the time of First World War. Turkey denies that the deaths constituted genocide, says the toll has been inflated and insists that those killed were victims of civil war and unrest. It has threatened sanctions against countries that use the term genocide.

Turkish President Abdullah Gul called the measure's passage "unacceptable," said Reuters.

"Unfortunately some politicians in the United States of America have closed their ears to calls to be reasonable and once again sought to sacrifice big problems for small domestic political games," state news agency Anatolian quoted Gul as saying.

Canada recognized the Armenian genocide in 2004, passing a parliamentary resolution denouncing the 1915 incident as a "crime against humanity."

Bush, Rice concerned

Bush made a last-minute push to persuade lawmakers to reject the measure.

"Its passage would do great harm to our relations with a key ally in NATO and in the global war on terror," Bush said hours before the vote.

Earlier, Secretary of State Condoleezza Rice and Defence Secretary Robert Gates conveyed their concerns.

Passing the measure "at this time would be very problematic for everything we are trying to do in the Middle East," Rice told reporters at the White House.

Turkey raised the possibility of impeding logistical and other U.S. military traffic now using Turkish airspace.

The vote comes at a time of tensionin the region. Turkey's government is seeking parliamentary approval for a military operation to chase separatist Kurdish rebels who operate from bases in northern Iraq. The move, opposed by the U.S., could open a new front in the most stable part of Iraq.

Gates said 70 per cent of U.S. air cargo headed for Iraq goes through Turkey, as does about one-third of the fuel used by the U.S. military in Iraq.

"Access to airfields and to the roads and so on in Turkey would very much be put at risk if this resolution passes and Turkey reacts as strongly as we believe they will," Gates said. He also said that 95 per cent of new vehicles designed to better protect passengers against mine attacks are being flown through Turkey to get to Iraq.

Lawmakers from both parties who supported the proposal said the moral implications outweighed security concerns and friendship with Turkey.

With files from the Associated Press