U.S. "gravely concerned" by continuing violence in Ukraine

The United States is "gravely concerned" by the deteriorating situation in eastern Ukraine and calls on rebels to immediately halt all attacks, the State Department said on Monday.

"These aggressive actions and statements by the Russia-backed separatists threaten the most recent ceasefire and jeopardize the planned withdrawal of heavy weapons, as called for in the February 12 Minsk packet of implementing measures," State Department spokeswoman Jen Psaki said in a statement.

On Thursday, leaders of Russia, Ukraine, France and Germany announced a peace deal that envisages a ceasefire between Ukrainian forces and rebels starting Sunday, followed by the withdrawal of heavy weapons from the front line and constitutional reform to give eastern Ukraine more autonomy.

The Organization for Security and Co-operation in Europe (OSCE) confirms that attacks continue in several locations in eastern Ukraine, including Debaltseve, Sievierodonetsk, Luhansk and Donetsk, Psaki said.

The spokeswoman cited the Ukrainian government as saying that "its forces have been fired on 129 times in the last 24 hours by Russia-backed separatists," which resulted in five deaths and 25 injuries.

The rebels have publicly declared that they refuse to observe the ceasefire in Debaltseve, and OSCE monitors have not been provided security guarantees for access, Psaki added.

The U.S. calls on Russia and the rebels to halt all attacks immediately, engage with the OSCE to facilitate the ceasefire, Psaki said, adding that the U.S. is closely monitoring reports of a new column of Russian military equipment moving toward Debaltseve. Endi