The head of NATO has called on Russia to stop supporting separatists in Ukraine and to work to find a political solution to the conflict.

General Anders Rasmussen spoke after meeting with the Polish foreign and defence ministers in Warsaw.

“Russia has been escalating this crisis from the start. Russia should live up to its international commitments and stop supporting separatists and pull back its troops from the Ukrainian border, so political solutions can be found to this great crisis,” General Rasmussen said.

Earlier Russian president Putin said he had pulled back his forces from the Ukrainian border; NATO said it had seen no evidence of this.

Meanwhile NATO has been bringing in troops to southern Poland. American, Canadian and Polish paratroopers took part in a show of strength with military exercises on Wednesday.

NATO said it would take any steps needed to “increase the security” of its allies in central and eastern Europe.