Washington ? Yielding to fierce diplomatic and political pressure, congressional sponsors of an Armenian genocide resolution abruptly put off a vote on the measure Thursday and defused a mounting confrontation with Turkey that was threatening to hamper the U.S. war effort in Iraq.

The decision was a swift reversal for the long-debated resolution, disappointing supporters who only two weeks ago were optimistic that the House would approve it. “We’re not going to bring it up until we’re confident we have the votes to pass it,” said Rep. Adam B. Schiff, D-Calif., who introduced the measure.

“It’s going to take some time.”

The action extricated House Speaker Nancy Pelosi, D-Calif., from the clash between a powerful constituency in California and an important U.S. military ally.

As the measure approached a vote, the Turkish government warned it could lead to a rupture in relations and disrupt U.S. military operations in Iraq. Most of the supplies headed to U.S. forces in Iraq are flown through Turkey. The issue also came up as the U.S. was imploring Turkey not to send forces into northern Iraq to curb Kurdish rebel attacks.