WASHINGTON -- Damascus largely froze high-level diplomatic efforts with the U.S. after an American strike inside the country, a move that threatens support for broader peace initiatives in the Middle East. Syrian officials on Monday sent a demarche to the American Embassy in Damascus in response to what it claimed was a U.S. cross-border helicopter attack inside eastern Syria on Sunday that killed eight people.
President Bashar Assad's government said it was largely freezing high-level diplomatic engagement with the Bush administration for its remaining three months in office.
Syrian diplomats said that before the raid they had been considering inviting to Damascus the State Department's point man on the Middle East, Assistant Secretary of State David Welch, for talks aimed on furthering Israeli-Syrian peace negotiations, as well as efforts to stabilize Lebanon and Iraq.
"Obviously, we're not going to be inviting Welch to Syria now," said Ahmed Salkini, spokesman for the Syrian Embassy in Washington. "Any sovereign country that is attacked unprovoked has the right to respond."
Pentagon and White House officials declined to comment on Syria's charges. Bush administration officials have regularly charged Syria with failing to stop the flow of foreign and al Qaeda fighters into Iraq.
The Associated Press reported the raid killed the al Qaeda-linked head of a Syrian network that smuggled fighters, weapons and cash into Iraq. The operation targeted the home of Abu Ghadiyah; the Treasury Department has named him as one of four major figures in al Qaeda's Iraq wing who were living in Syria.
Relations between the U.S. and Syria had shown signs of improving in recent weeks.
Late last month, Secretary of State Condoleezza Rice and Mr. Welch held rare face-to-face meetings with Syrian Foreign Minister Walid Moallem in New York. Both sides said they hoped to follow up the meetings by developing a more regular dialogue focused on Middle East security issues.
Ms. Rice particularly praised Damascus's pursuit of peace talks with Israel and its decision to open formal diplomatic relations with Lebanon. Mr. Moallem said he sought greater cooperation with the U.S. in confronting al Qaeda and other extremist groups in the region.
The Bush administration froze most high-level engagement with Syria following the 2005 murder of former Lebanese Prime Minister Rafik Hariri. A United Nations probe has implicated Syrian intelligence officials in the assassination.
Democratic presidential candidate Barack Obama has said that if elected he would seek to directly engage Syria in a bid to win its support for stabilization efforts in the Middle East. The Republican Party's candidate, John McCain, also has been supportive of the Israel-Syria peace track.
Still, Sunday's attack appears to be a signal that the Pentagon is taking an increasingly aggressive stance against countries that appear to be aiding militant groups, whether it's Syria or Pakistan. This doesn't mean, however, that this rules out diplomacy occurring at the same time.
The American cross-border attack has also sent jitters to Iraq's other neighbors, namely Iran. Syria and Iran have been opposing Iraq signing the Security of the Forces Agreement with the U.S., and have expressed anxiety that the U.S. could use its military bases in Iraq to stage cross-border attacks on their soil. —Farnaz Fassihi in Beirut contributed to this article.
Write to Jay Solomon at jay.solomon@wsj.com