NATO today accused Russia of sending fresh columns of tanks, troops and military hardware into Ukraine as Kiev said it was preparing for a return to combat in the war-torn east.
Ukraine's warning will fuel fears of a return to all-out conflict despite a two-month-old ceasefire deal which has halted fighting along much of the frontline but not stopped shelling at strategic flashpoints.
Defence Minister Stepan Poltorak said Kiev was getting set for a possible new round of fighting after seeing "increased activity" by Russia and pro-Moscow rebels across the region.
"The main task I see is to prepare for combat operations. We are doing this, we are readying our reserves," Poltorak said at the start of a cabinet meeting.
"We observe their movements, we know where they are and we expect unpredictable actions from them."
He said the situation in the conflict zone was "complicated but stable" for now.
His comments came as NATO's supreme commander threw his weight behind allegations that Moscow has stepped up the flow of armaments across the frontier in the past few days, the first such accusations from the US-led alliance since the signing of the truce deal September 5.
"We have seen columns of Russian equipment, primarily Russian tanks, Russian artillery, Russian air defence systems and Russian combat troops entering into Ukraine," US General Philip Breedlove said in Sofia.
Moscow immediately rejected the allegations, the latest in stream of denials that it is involved in the fighting that has rocked east Ukraine since early April.
"We have stopped paying attention to unfounded statements by NATO's Supreme Allied Commander Europe General Philip Breedlove about his 'seeing' Russian military columns," defence ministry spokesman Igor Konashenkov told Russian news agencies.
Russia, however, openly gives political backing to the self-declared separatist statelets and it is unclear how else the rebels could have acquired the heavy weaponry typical of a regular army.
