EU foreign policy chief Catherine Ashton held "useful" talks in Madrid Tuesday with Russian Foreign Minister Sergei Lavrov over the spiraling crisis in Ukraine, a European source said.

"We had a useful discussion which lasted over an hour," a European diplomatic source quoted Ashton as saying after the meeting held in the Russian ambassador's residence in Madrid.

The Russian foreign minister then met Spanish Prime Minister Mariano Rajoy and Spanish King Juan Carlos.

Lavrov is scheduled to meet Spanish Foreign Minister Jose Manuel Garcia Margallo on Wednesday.

Earlier on Tuesday, Lavrov said that threats of sanctions against Moscow were counter-productive and would not change its position on the Ukraine crisis.

"Our position is honest and... will not change," he told a news conference in Tunisia, where he was on an official visit.

"We have always opposed the policy of unilateral sanctions. I hope our partners understand that such actions are counter-productive."