"We call on the Russian-led forces to implement a genuine ceasefire and especially to cease shelling around the filtration plant and withdraw heavy weapons to the agreed-upon lines," Nauert said at a briefing in Washington, D.C., on November 7, 2017.

According to her, in eastern Ukraine two water filtration plants have been subjected to shelling in recent days. "It is considered especially dangerous because some shells have fallen as close to as 50 meters from chlorine gas storage tanks at the facilities. A hit on the tanks would cause a major catastrophe, gassing people at the plant, possibly even those in nearby towns, as well as disrupting the supply of clean drinking water in the area," she said.

Read alsoEscalation in Donbas: 17 attacks on Ukraine troops, 2 KIA's, 3 WIA's in last dayIn her words, the Minsk peace agreements on Donbas call for a full ceasefire along the line of contact, "a ceasefire that Russian-led forces have never fully respected."

"We also urge Ukraine to show restraint and to do everything within its power to implement the Minsk agreements," she added.