US Secretary of State John Kerry met with NATO allies and EU officials in Brussels on Tuesday.
The United States wants to impose further sanctions on Russia if separatists continue fighting in east Ukraine.
However EU diplomats are less keen and say they would only consider it if the situation seriously deteriorates.
At a press conference, Kerry repeated claims he has made previously that Russia has been arming rebels in East Ukraine.
“Since the September 5th, Minsk ceasefire agreement, Russia has funnelled several hundred pieces of military equipment and material including tanks, armoured personnel carriers and heavy artillery pieces directly to pro-Russian separatists in Ukraine,” he said.
Moscow denies supporting the separatists militarily.
At the meeting, NATO’s chief confirmed a new interim quick-reaction military force to respond to threats which will be in place by early 2015. It will later be replaced by a permanent force.