Ukraine could introduce martial law if eastern fighting worsens - Poroshenko

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 did not rule out introducing martial law and a new wave of military mobilisation if the conflict with pro-Russian separatists worsened.

Poroshenko made his comments as fresh tension with Russia over Crimea reignited fears that a fragile ceasefire deal hammered out in the Belarussian capital Minsk in February 2015 could collapse following the deadliest month of fighting in a year.