KYIV, Jan 22 - U.S. envoy Steve Witkoff on Thursday said "a lot of progress" had been made in Ukraine peace talks and that negotiations were down to one last issue, as Ukraine's Volodymyr Zelenskiy arrived in Switzerland for talks with U.S. President Donald Trump.

Zelenskiy had said earlier this week that he would not attend the annual World Economic Forum in Davos and would remain in Kyiv to focus on the energy crisis in Ukraine, where Russian airstrikes against electricity infrastructure have left swathes of the capital and other regions without power.