WASHINGTON — A congressional panel defied President Bush yesterday and approved a measure that he said would damage American 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 American 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 Mr. 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.

Mr. 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,” Mr. Bush said hours before the vote.

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

Earlier, Secretary of State Rice and Defense Secretary 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,” Ms. Rice told reporters at the White House.

Mr. Gates said 70% of American air cargo headed for Iraq goes through Turkey, as does about one-third of the fuel used by the American military in Iraq.

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 America, could open a new front in the most stable part of Iraq.

“I have been trying to warn the [American] lawmakers not to make a historic mistake,” said Egemen Bagis, a close foreign policy adviser to Prime Minister Erdogan of Turkey.

Yet with the House’s first order of business yesterday, the speaker, Rep. 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.”

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,” Rep. Chris Smith, a Republican of New Jersey, said. “For Armenians everywhere, the Turkish government’s denial is a slap in the face.”

The American Embassy in Ankara warned American citizens in Turkey about “demonstrations and other manifestations of anti-Americanism” if the bill moved ahead. Protests were reported yesterday outside the embassy and the American consulate in Istanbul. Ms. Pelosi and the second-ranking Democrat in the House, the majority leader, Rep. Steny Hoyer, met yesterday with the Turkish ambassador, Nabi Sensoy, but emerged from the meeting unswayed. Mr. Hoyer told reporters he expects a floor vote on the measure before the House adjourns for the year.

Mr. 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.”