US allies said they had won assurances on Friday from new Secretary of State Rex Tillerson that Washington supports a political solution to the Syria conflict, ahead of UN peace talks.

On the sidelines of a G20 gathering in Germany, Tillerson joined representatives of several countries that support the Syrian opposition for talks on a way to end the nearly six-year war.

"All the participants want a political solution because a military solution alone won't lead to peace in Syria," German Foreign Minister Sigmar Gabriel told reporters in Bonn, adding that "Tillerson became very involved in the debates".