By Vladimir Soldatkin VLADIVOSTOK, Russia, Sept 3 (Reuters) - Russian President Vladimir Putin said on Thursday there was a chance of a peace agreement to end the war in Ukraine, but restarting talks was harder because of Ukrainian attacks on shipping and a call by Kyiv for civilian aircraft to avoid Russian airspace.

Contacts with Kyiv are continuing mostly at the level of the security services, though it's difficult to say whether they'd lead to a peace agreement, Putin said.