KIEV, May 22 (Xinhua) -- Ukraine has requested a U.N. Security Council emergency meeting to help deal with the crisis in its eastern regions and stop alleged aggression from Russia, Prime Minister Arseny Yatsenyuk said Thursday.
"We are ready to provide proof that the Russian side made attempts to escalate the conflict and bloodshed, capture Ukrainian border crossings and disrupt the presidential elections," Yatsenyuk told reporters.
He said Ukrainian law enforcers had "irrefutable evidence" there were centers in Russia, which "provide training for members of illegal armed groups that operate in Ukraine."
Tensions in Ukraine are high after an attack on an army checkpoint in Donetsk region early Thursday, with one report claiming at least eight Ukrainian troops were killed and 18 injured.
Later in the day, the leadership of a self-proclaimed republic in the neighboring Lugansk region, declared martial law and asked Russia to send troops to "protect civilians".
The development came just a day after the Russian Defense Ministry said troops involved in military exercises near the border with Ukraine were returning to their bases.