"We are seeing a steady demonstration of the escalation of the situation in the east, the number of shell attacks has risen, and our reaction has been instant. My order has been clear: as soon as the lives of our military, our warriors, our heroes are at risk, the Ukrainian military have the right to open fire in response," Poroshenko said in an interview with Ukrainian television channels on Sunday. Recently the Ukrainian military have destroyed four sabotage groups, one of which had come as close as was possible to a Ukrainian military observation post, he said. "The group was destroyed, and documents confirming Russian citizenship of those who carried out this attack were found among the things left behind," Poroshenko said. This is yet another proof of the Russians being involved in the hostilities in eastern Ukraine, he said. "We have sharply increased our combat readiness and steps the Ukrainian army will take in defense. We are holding necessary meetings right now and with the OSCE SMM [Special Monitoring Mission to Ukraine] on Monday. We clearly point to the locations which, our intelligence says, store the removed heavy weaponry and artillery," he said. The president added that there has been an increase in the number of Ukrainian military casualties. "We stress that the lion's share (90%) are losses from land mine and booby-trap explosions," he said, adding that the Ukrainian authorities are especially keen on launching the demining campaign in the country's east as soon as possible. In particular, agreement has been reached with the European Union over financial aid for the demining, he said. "We are deploying bomb disposal experts under the OSCE aegis and doing all we can to remove the mines," he said.