A U.S. congressional panel defied President Bush on Wednesday and approved a measure that he said would damage U.S. goals in the Middle East.

The measure that would recognize the World War I-era killings of Armenians as a genocide had been strongly opposed by Turkey, a key NATO ally that has supported U.S. efforts in Iraq.

The House Foreign Affairs Committee's 27-21 vote now sends the measure to the House floor — unless the Democratic leadership reverses course and heeds Bush's warnings.

At issue is the killing of up to 1.5 million Armenians by Ottoman Turks around the time of World War I. 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.

Bush and other senior officials had made a last-minute push to persuade lawmakers on the Foreign Affairs Committee 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.

The Foreign Affairs Committee's Chairman, Rep. Tom Lantos, D-Calif., warned of the potential fallout if the proposal passed. Lantos, a Hungarian-born survivor of the Holocaust, supported a similar resolution two years ago.

"We have to weigh the desire to express our solidarity with the Armenian people ... against the risk that it could cause young men and women in the uniform of the United States armed services to pay an even heavier price than they are currently paying," Lantos said.

The Massachusetts congressional delegation has supported the measure.

"I believe that by passing this resolution, we will contribute to the process of rebuilding relations between Armenians and Turks and help heal the wounds from that dark period of history," Rep. Edward Markey, D-Mass., whose district includes Watertown and other suburbs that are home to a large Armenian-American population, said in a statement.

Rep. William Delahunt, D-Mass., a Foreign Affairs panel member, voiced support for the measure at the hearing.

The issue flared in Massachusetts a few months ago. A local Anti-Defamation League leader was fired after saying he agreed the killings were genocide. Days later, the ADL reversed its stance, saying the killings were "tantamount to genocide." The man was rehired.

Critics had questioned how a group dedicated to remembering Holocaust victims could be credible without recognizing the Armenian killings as genocide.

In the fight over the congressional resolution, Turkey raised the possibility of impeding logistical and other U.S. military traffic now using Turkish airspace.

Earlier, Secretary of State Condoleezza Rice and Defense 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.

The vote comes at a tense time in 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.

"I have been trying to warn the (U.S.) lawmakers not to make a historic mistake," said Egemen Bagis, a close foreign policy adviser to Turkey's prime minister, Recep Tayyip Erdogan.

Yet with the House's first order of business Wednesday, Speaker Nancy Pelosi made clear that Turkey's position was a hard sell. She introduced the Supreme Patriarch of all Armenians, Karekin II, to deliver the morning prayer — a daily ritual intended to be apolitical.

"With the solemn burden of history, we remember the victims of the genocide of the Armenians," Karekin said in the House. "Give peace and justice on their descendants."

Gates said 70 percent 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 percent of new vehicles designed to better protect 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.

"The sad truth is that the modern government of Turkey refuses to come to terms with this genocide," said Rep. Chris Smith, R.-N.J. "For Armenians everywhere, the Turkish government's denial is a slap in the face."

The vote comes at a tense time in 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.

"I have been trying to warn the (U.S.) lawmakers not to make a historic mistake," said Egemen Bagis, a close foreign policy adviser to Turkey's prime minister, Recep Tayyip Erdogan.

Yet with the House's first order of business Wednesday, Speaker Nancy Pelosi made clear that Turkey's position was a hard sell. She introduced the Supreme Patriarch of all Armenians, Karekin II, to deliver the morning prayer — a daily ritual intended to be apolitical.

"With the solemn burden of history, we remember the victims of the genocide of the Armenians," Karekin said in the House. "Give peace and justice on their descendants."

Pelosi spokesman Nadeam Elshami said the timing of Karekin's visit was a coincidence. Rep. Joe Knollenberg, a Republican, had requested the leader deliver a morning prayer earlier this year. The House chaplain arranged the visit based on Karekin's schedule and was not aware of the committee's plans, Elshami said.

The U.S. Embassy in Ankara warned U.S. citizens in Turkey about "demonstrations and other manifestations of anti-Americanism" if the bill moved ahead. Protests were reported Wednesday outside the embassy and the U.S. Consulate in Istanbul.

Pelosi and the second-ranking Democrat in the House, Majority Leader Steny Hoyer, met Wednesday with Turkish Ambassador Nabi Sensoy but emerged from the meeting unswayed. Hoyer told reporters he expects a floor vote on the measure before the House adjourns for the year.

Hoyer said he hoped that Turkey would realize it is not a condemnation of its current government but rather of "another government, at another time."