KIEV, May 13 -- Visiting European Council President Herman Van Rompuy met with Ukrainian Prime Minister Arseny Yatsenyuk to discuss ways to stabilize the situation in Ukraine ahead of the May 25 presidential election, the government's press service said Tuesday.

At a briefing following the meeting on Monday, Van Rompuy denounced the referendums on independence in Donetsk and Lugansk regions and Crimea's joining into Russia.

"The European Union strongly supports the unity and sovereignty, independence and territorial integrity of Ukraine. We do not accept the annexation of the Crimea and Sevastopol and we do not recognize the so-called referendum," Van Rompuy told reporters.

For his part, Yatsenyuk pledged to hold dialogue with protesters in the east and asked the international community to mediate the talks.

"We support such negotiations only if they are attended by Ukraine, the EU, the U.S. and Russia," Yatsenyuk said.

Also on Monday, Van Rompuy held talks with Ukrainian acting President Alexandr Turchynov to discuss the tension in eastern Ukraine, the upcoming presidential elections and visa facilitation between the two sides.

According to a statement issued by the presidential press service, Turchynov reiterated his country's commitment to following the course for integration with the EU and pledged to ensure a free and fair election.

Van Rompuy said the EU will do its best to help restore stability in Ukraine.