A congressional committee voted Thursday to label as "genocide" the Ottoman-era slaughter of Armenians, shrugging off a last-minute warning from Obama administration officials worried about alienating Turkey, a key ally in the Middle East.

Secretary of State Hillary Rodham Clinton called Rep. Howard L. Berman (D-Calif.), chairman of the House Foreign Affairs Committee, on the eve of the hearing to express concern, administration officials said. In addition to straining U.S. relations with Turkey, the resolution could also endanger a recent rapprochement between Turkey and Armenia, State Department officials said.

But the committee voted 23 to 22 to adopt the measure. It calls on President Obama to use the annual presidential statement on the tragedy next month to "characterize the systemic and deliberate annihilation of 1,500,000 Armenians as genocide." The non-binding measure could now be taken up by the full House.

The issue is awkward for the Obama administration, which had said little publicly before the vote. As senators, Obama, Vice President Biden and Clinton had all called on the White House to condemn the killings as genocide. As president, however, Obama has not done so.

Turkey strongly denies the genocide charge. It has been a key U.S. ally, allowing use of one of its bases to move supplies to Iraq....