The European Union on Monday warned Moscow against recognizing the self-proclaimed Donetsk and Luhansk people's republics in eastern Ukraine, promising a strong response if Russia decides to do so, Reuters reported.

"If there is annexation, there will be sanctions, and if there is recognition, I will put the sanctions on the table and the ministers will decide," the EU's foreign policy chief Josep Borrell said after a meeting of the bloc's foreign ministers.

"We call on President Putin to respect international law," he said. "We are ready to react with a strong united front in case he should decide" to ignore these calls, he said.