NATO Secretary General Jens Stoltenberg accuses Russia of a "serious military buildup" both inside eastern Ukraine and on the Russian side of the border, dpa reported. "We see the movement of troops, of equipment, of tanks, of artillery and also advanced air defence systems," Stoltenberg says ahead of talks with EU defence ministers. "We call on Russia to pull back its forces from eastern Ukraine and to respect the Minsk agreements," he adds. "Russia has a choice. Russia can either be part of a peaceful negotiated solution or Russia can continue on the path of isolation," the NATO chief says.