Speaking at a press conference with her French counterpart Michel Barnier during a London meeting on strengthening the Palestinian Authority, Rice said the pair had had constructive talks and had committed themselves to helping Lebanon in every way possible.
Syria was "out of step" with the direction the region was taking and with the wishes of the people, she said.
The United States and France would ensure there was no foreign interference in Lebanese affairs and would support free and fair elections in the country, she continued.
They would also look at what could be done to help the Lebanese stabilize the situation "should that become necessary."
Barnier said United Nations Resolution 1559 -- which calls on Syria to withdraw its troops from Lebanon -- was a "very clear" resolution backed by the international community.
"There can be absolutely no excuses to postpone its implementation or not implement it at all," he said.