Kerry and Putin set for vital talks on Ukraine

US Secretary of State John Kerry arrived in the Russian resort of Sochi on Tuesday for high-stakes talks with Russian President Vladimir Putin that US officials said would push for the full implementation of a shaky Ukraine cease-fire.

Kerry was scheduled to meet Putin in the Black Sea city at "a critical moment", with Ukraine aiming to ensure the "next steps in concrete implementation" of the cease-fire deal are taken, a senior US official said.

Kerry was to lay a wreath at a World War II memorial in the resort before meeting Putin and Russian Foreign Minister Sergey Lavrov during the brief visit, his first to Russia since May 2013.