"The United States welcomes the trilateral contact group's announcement of an agreement for a holiday ceasefire in eastern Ukraine – excuse me – set to begin on Christmas Eve at midnight," U.S. State Department spokesperson John Kirby said at a daily press briefing in Washington, DC, on December 22.

"We hope that the ceasefire will mark the beginning of sustained quiet at the line of contact to allow Ukrainians on both sides of the line to live in peace and security," he stressed.

"And as we've said before, we're deeply concerned by the recent spike in violence in eastern Ukraine in which combined Russian-separatist forces have launched daily attacks on Ukrainian positions using heavy weaponry prohibited by the Minsk agreements."

Read alsoU.S. alarmed by spike in violence in eastern Ukraine"Once again, we urge Russia to use its influence with the separatists to turn down the violence, as it has done successfully numerous times in the past, and allow access for OSCE monitors. This will relieve the humanitarian suffering in eastern Ukraine, and it will create space for further progress on the implementation of the Minsk agreements," Kirby said.