U.S. Secretary of State John Kerry is dismissing posturing from the Syrian government and opposition ahead of U.N.-led peace talks that are supposed to begin this week.

Speaking to reporters in Laos, Kerry says that recent statements from Syrian officials that they will make no concessions at the negotiating table and complaints from opposition figures that they are being forced into the talks reflect only "tensions" and "rumors." He also is denying suggestions of disunity among countries that back the opposition and says U.S. support for foes of President Bashar Assad remains solid.

The talks are due to begin on Monday in Geneva but will almost certainly be delayed because of disagreements with Russia and Iran, which support the Syrian government, over which groups can represent the opposition.