Rice made the call while travelling home from a Pacific Rim summit with US President George W. Bush, State Department deputy spokesman Tom Casey said.
"Secretary of State Rice has called Prime Minister Siniora to express her condolences and also to reiterate her support and the support of the United States for Lebanese democracy and for the Siniora government," he said.
Earlier, Rice's top aide called the killing of cabinet minister Pierre Gemayel an "act of terrorism" aimed at intimidating Syria's opponents in the country, which was controlled by Damascus until it withdrew its troops from the country last year.

Copyright AFP (Agence France-Presse), 2006