Syrian warplanes pounded a rebel-held town near the Lebanese border on Wednesday, activists said, as opposition leaders in Geneva called on Russia to put pressure on the government to prevent the faltering peace negotiations from collapsing.

A second round of talks that started in Geneva Monday is mired in acrimony as government and opposition delegates hurl accusations back and forth, unable to agree on a common agenda.

During a meeting with U.N. mediator Lakhdar Brahimi Wednesday, the opposition delegation submitted a paper containing their vision for a political transition. The proposal calls for the expulsion of all foreign fighters from Syria and a U.N. monitored cease-fire in Syria — but the Syrian deputy foreign minister dismissed it as a “show” and refused to discuss it.