"In the event of the exacerbation of the situation in the east and in Crimea [...] we will have to impose martial law and order mobilization," he said at a ceremony commemorating pilots killed in the ATO zone, which was held in the town of Brody in Lviv region.

Read alsoRussian proxies attack Ukraine 96 times in last day amid escalationJointly with its international partners, Ukraine "will be able to force the aggressor to sit at the negotiating table, force it to comply with its obligations in the Minsk process, and return to the Normandy format," he said.

Read alsoForeigners in ATO: Three years without citizenshipSince the beginning of 2016, over 45,000 Ukrainians have concluded contract to serve in the army, the president recalled. "They spoke about contracts in the army before us – but nothing was done. As of today these military volunteers who have concluded contracts have let me, as commander-in-chief, not to announce new waves of mobilization," he said.