HELSINKI—U.S. Secretary of State Hillary Rodham Clinton is in Finland, opening a three-country European tour that could be extended if a proposed international conference on Syria goes ahead this weekend.

Clinton arrived in Helsinki early Wednesday and is to visit Latvia and Russia ahead of the Syria meeting that U.N. envoy Kofi Annan (KOH'-fee AN'-nan) is trying to organize for Saturday in Geneva. Clinton expects to attend if she is convinced that Annan's plan for political transition in Syria will be endorsed.

The U.S. and Russia differed over whether Iran should participate in the conference, with Washington opposed and Russia in favor. Russian Foreign Minister Sergey Lavrov said Tuesday that he would go even if Iran did not.

Clinton is to meet Lavrov on Friday in St. Petersburg.