Reinforced police and National Guard units will be patrolling Kyiv, Odesa, Kharkiv and Dnipropetrovsk ahead of May 9, said Ukrainian Prime Minister Arseniy Yatseniuk.

"Security will also be tightened in other cities should reports arrive about tensions or provocations," he said in an interview with the Ukraina television and radio station.

All other cities will be patrolled by reinforced police units, he said.

"The situation is being artificially escalated, including in the time to go before the May events, by anti-Ukrainian forces in accordance with the classical Russian scenario which aims to destabilize the country," Yatseniuk said.