The Ukrainian side does not expect any serious breakthrough to be made at talks of the 'Normandy format' leaders (Ukraine, Germany, France and Russia) expected to take place in Berlin on Wednesday, Ukrainian President Petro Poroshenko said.

"We have no heightened expectations of this meeting," Poroshenko said at a joint press conference with Norwegian Prime Minister Erna Solberg in Oslo on Tuesday, when answering a question from Interfax-Ukraine.

Today it is important to stop the Russian aggression in Ukraine and restore control over the country's borders, he said.

"What we are having is not an internal conflict. Rather, it is Russian occupation, Russian aggression against the independent and sovereign state of Ukraine in the center of Europe in the 21st century," Poroshenko said.

Ukraine has implemented 95% of the political package of the Minsk Agreements, but "Russia has implemented 0% of the security package," he said.