President Bush's spokesman says Syria needs to pull all its forces out of Lebanon now.
Scott McClellan says the plan announced by Syrian President Bashar al-Assad and his Lebanese counterpart, Emile Lahoud, falls far short.
"We want to see the complete and immediate withdrawal of all Syrian military forces and all intelligence services in Lebanon," he said. "This is a half-measure that simply does not meet that objective."
Under the plan, Syrian forces will redeploy to border areas in Lebanon by the end of March, with a timetable for a full withdrawal to be determined later.
The White House spokesman says it does not meet demands set by the United Nations.
"We believe they need to focus on the Security Council resolution that was passed last year - resolution 1559 - which calls for an end to all foreign occupation of Lebanon, and which also calls for support for free and fair elections, and calls for a sovereign and independent Lebanon," he said.
Mr. McClellan spoke to reporters as protests against the Syrian presence continued in the streets of Beirut. He said the Lebanese people are showing their desire to live in freedom.
"And, we want to see the Syrian and Lebanese governments respect the will of the Lebanese people," he said. "The United States, like the rest of the international community, stands with the Lebanese people."
Syria has had troops in neighboring Lebanon since 1976, when they were sent in during that country's civil war. They remained when the war ended.
Pressure has grown in recent weeks for a complete withdrawal of Syrian forces from Lebanon following the assassination of former Lebanese Prime Minister Rafik Hariri. He was killed in a car bombing last month in central Beirut.