KIEV, Ukraine -- The head of the NATO alliance urged Russia Thursday to "step back from the brink" by withdrawing its troops massed on the Ukrainian border or face greater isolation and debilitating sanctions.
"Do not use peacekeeping as an excuse for war-making," said NATO Secretary General Anders Fogh Rasmussen, pointedly speaking from Kiev, where he visited to show support.
NATO has warned that Russia could invade Ukraine under the pretext of sending in a peacekeeping mission to stop the war between government troops and pro-Russian separatists. Russia has as many as 20,000 troops at the border.
Rasmussen met with Ukrainian officials, offering intensified NATO assistance to the military in the form of advisers, training and logistical support.
"I have no doubt the international community would react decisively, with broader, deeper, tougher economic sanctions if Russia intervenes further," Rasmussen told reporters.
NATO has made clear it does not want to send troops to protect Ukraine, which is not a member country.
Rasmussen's remarks came amid new fighting in the east, where government troops mounted an offensive against the rebels. In Donetsk, mortar shells struck three apartment buildings and the dentistry wing of Vishnevskiy Hospital, where one person died. Many residents say the military is responsible for the shelling. The military insists its artillery is directed only at convoys delivering ordnance to the rebels.
Also Thursday, Ukraine accused Russia of holding dozens of military officers and border guards who were among hundreds who fled to Russia to escape heavy bombardment. A spokesman said 18 officers and 28 guards could not leave.