NATO chief concerned at increase in Ukraine violence

REYKJAVIK (Reuters) - NATO Secretary-General Jens Stoltenberg voiced concern on Thursday over an increase in violence and movements of heavy military equipment in eastern Ukraine, saying they were undermining the Minsk peace agreement.

Ukraine's military has reported that at least eight soldiers have been killed in the east this week despite a two-month-old ceasefire deal.

The Ukrainian army and pro-Russian separatists accuse each other of stepping up attacks and building up weaponry on the front line.

"We are very concerned about the increased violence in eastern Ukraine and we have seen more violations of the ceasefire," Stoltenberg told reporters during a visit to Iceland.

"We have seen more movement of heavy equipment and therefore we are of course very concerned because this is undermining the ceasefire and the whole Minsk agreement."

He urged both sides to respect the ceasefire and implement the Minsk accord.

"I also call on Russia to stop supporting the separatists and to make sure that they use all their influence over the separatists so they are respecting the ceasefire and withdrawing their weapons from the ... front line," he said.

President Vladimir Putin said on Thursday Russian military forces were not in Ukraine, denying allegations by Ukraine and Western countries that Moscow is providing troops and support for pro-Russian rebels.

(Reporting by Ragnhildur Sigurdardottir; writing by Adrian Croft in Brussels; editing by Andrew Roche)