U.S. and Russian participants have met in Switzerland for unofficial talks about the Ukraine war in recent months, including as recently as last week, three sources with knowledge of the matter said.

The United States and Russia will appoint high-level teams to negotiate the end of the war in Ukraine and are working to reestablish diplomatic channels, US Secretary of State Marco Rubio said at the end of key talks that excluded Kyiv.

Moscow’s forces are three miles from Dnipropetrovsk, a province they have never invaded. If they cross in, the advance would be a morale blow to Ukraine and complicate any territorial negotiations.