"There are continued attacks against civilian infrastructure projects in Donetsk. It's sad that we have to address this once again," Nauert said.
She said that the situation in eastern Ukraine was not improving.
"The United States continues to be deeply concerned by the escalating violence and the worsening humanitarian situation in eastern Ukraine," Nauert said.
At the same time, she recalled that back in November, the Department of State had already expressed concern about shelling near a vital water filtration plant in Donetsk.
"The plant remains under threat, and now a nearby coke factory has also taken fire by Russian-led forces," Nauert said.
She said that together, the filtration plant and this coke factory help provide drinking water, electricity, and central heating to approximately 345,000 people. In this regard, she said that threatening water supplies and also home heating in the dead of winter was simply unconscionable.
"Russian-led forces should immediately withdraw from their new positions surrounding the water treatment plant. We again call on Russia to stop artillery and rocket attacks against Ukrainian civilian areas and to honor the ceasefire called for in the Minsk agreements," Nauert said.
She also said that the humanitarian situation in eastern Ukraine "is one of the worst it has been now in three years and it is deteriorating."
"We call on Russia to take immediate steps to resolve the humanitarian crisis by withdrawing its forces and agreeing to a robust UN peacekeeping mission," Nauert said.
On Sept. 5, Russian President Putin said deployment of U.N. peacekeepers in the Donbas was quite appropriate for solving of the conflict in the region, but only along the line of contact and with the aim of protecting the OSCE mission.
Ukraine's representative in Humanitarian subgroup of the Tripartite contact group in Minsk talks, deputy speaker of Ukrainian parliament Iryna Herashchenko commented on Putin's statement and said the Kremlin scenarios will fail; peacekeepers must be introduced across all Russia-occupied territories.