"We must end the fighting this week. For me, every day in which people die, every day in which Ukraine pays such a high price, is unacceptable," Poroshenko said in a statement published on his official website on Sunday.

"And to do that, we must restore the Ukrainian border so that the safety of each Ukrainian citizen is guaranteed," he added.

The death toll from fresh clashes between Ukrainian forces and independent-seeking militants in eastern Ukraine reached 181, Ukraine’s acting prosecutor general said last week.

His comments followed a round of talks with Moscow's ambassador to Kiev and an envoy from the Vienna-based Organization for Security and Cooperation in Europe (OSCE), and came a day after the 48-year-old confectionery tycoon was sworn into office as the fifth post-Soviet president of Ukraine.

Russian President Vladimir Putin issued orders on Saturday for security at the mutual border to be stepped up - a move demanded by both US President Barack Obama and several European heads of state.

In a separate development, Ukraine, Russia and European Commission officials will meet in Brussels on Monday evening to continue talks on how to resolve a dispute over gas prices.

The trilateral meeting, initiated by the Commission, is scheduled to start at 1700 GMT, with European Union Energy Commissioner Guenther Oettinger, Russian Energy Minister Alexander Novak and Ukrainian Energy Minister Yuri Prodan in attendance.

On May 12, Donetsk and Luhansk declared independence following local referendums, in which the regions’ residents voted overwhelmingly in favor of independence from Kiev.

Ukraine’s mainly Russian-speaking parts in the east have been the scene of deadly clashes between pro-Moscow forces and the Ukrainian army for weeks now. On June 2 alone, at least 10 people, including several civilians, were killed during Kiev’s military operations in Lugansk.

NTJ/MB