U.S. Pressures Ukraine to Negotiate Over Donetsk Region
Russia's offensive threatens key eastern Ukrainian cities.
Kyiv cites Russia's military advantage and harsh weather for the withdrawal.
Kyiv denies Russian claims of capturing Siversk.
Russian forces are near Sloviansk, 30 km from Siversk.
U.S. diplomatic pressure grows for negotiations in Donetsk.
Russia's slow advance through Donetsk marks the war's fourth year.
President Putin's threat intensifies the conflict.
3 weeks ago