Ukraine's President Petro Poroshenko gestures as he speaks during a joint press conference at the PGE National Stadium, the venue of the NATO summit, in Warsaw, Poland July 9, 2016. REUTERS/Kacper Pempel

KIEV (Reuters) - Ukrainian President Petro Poroshenko said on Thursday he had instructed all military units near Crimea and in the easterly Donbass region to be at the highest level of combat readiness, following Russian allegations of a Ukrainian incursion into Crimea.

Separately, the spokesman for Ukraine’s General Staff told Reuters that Ukraine had been holding scheduled military exercises in southern Ukraine since Wednesday.

Russian President Vladimir Putin accused Kiev on Wednesday of using terrorist tactics to try to provoke a new conflict and destabilise Crimea, which Moscow annexed from Ukraine in 2014. Ukraine dimissed the allegations as a cynical pretext for Russia to make more military threats against Ukraine.