"We have seen an increase in Russian equipment inside eastern Ukraine… like tanks, artillery, armored vehicles and advanced air defense systems," Stoltenberg said at a press briefing.
Earlier in the day, speaking at the World Economic Forum in Davos, Switzerland, Ukrainian President Petro Poroshenko claimed there were "more than 9,000 troops of the Russian Federation on my territory, including more than 500 tanks and heavy artillery and armed personnel carriers."
"We will not go into specific figures or numbers," Stoltenberg said.
Since the launch of the military operation against independence supporters in the southeast of Ukraine in April 2014 by Kiev authorities, the West has accused Russia of involvement in the conflict. In particular, NATO has accused Moscow of delivering arms and equipment to the militia in the region. However, Russia has repeatedly denied this claim.
