Russian on Monday urged the United States to do everything in its power to bring the Syrian opposition to peace talks after a key opposition group said it would not attend a proposed conference in Geneva.

"We very much expect our American partners and other countries, which not only have influence on various opposition groups but also ... encourage these opposition groups ... to realise their responsibility for creating conditions for performing their share of the work for convening Geneva 2," Russian Foreign Minister Sergei Lavrov said.