US warns Russia as Kremlin talks about war threat in Ukraine

US secretary of state Antony Blinken, left, and Russian foreign minister Sergey Lavrov in Sweden (Jonathan Nackstrand/Pool Photo via AP)

The Kremlin has voiced concerns about a possible escalation of fighting in a separatist conflict in eastern Ukraine as the US issued a strong warning to Russia to stay away from the area.

Ukrainian and Western officials have expressed concerns about a Russian troop buildup near Ukraine, fearing it could herald an invasion.