BRUSSELS (REUTERS) - Ukraine's armed forces will act if Russian military intervention escalates any further in to Ukraine's territory, Ukraine's Prime Minister Arseniy Yatsenyuk told a news conference on Thursday.

"In case of further escalation and military intervention into the Ukrainian territory by foreign forces, the Ukrainian government and Ukrainian military will act in accordance with the constitution and laws," Yatsenyuk said in Brussels.

"We are ready to protect our country," he said.

Ukrainian forces have so far not responded to the Russian takeover of the Crimean peninsula. But this could change if the Russian intervention escalated, he said.

Yatsenyuk, who came to Brussels to discuss the crisis with the leaders of the 28 countries of the European Union, said the talks with EU leaders were only about political and peaceful means of resolving the conflict.