ST. PETERSBURG, Russia (AP) — German Chancellor Angela Merkel is doubtful that world leaders can agree on what to do about Syria's civil war, despite frenzied diplomatic efforts following a chemical weapons attack.

Merkel told reporters Thursday at a summit of the Group of 20 leading world economies that because of disagreement over who was responsible for the poison gas attack last month, "I do not believe yet that we will reach a joint position."

The United States and France are trying to rally international support at the G-20 summit for a possible military intervention against Syrian President Bashar Assad's regime over the chemical attack. Merkel insisted that Germany wouldn't get involved militarily, but could provide humanitarian aid and political support.

Summit host Vladimir Putin supports Syria's government and opposes intervention.