U.S. 'gravely concerned' by fighting in eastern Ukraine

WASHINGTON (Reuters) - The United States said on Monday it is "gravely concerned" by fighting in and around Debaltseve in eastern Ukraine that flared up after a ceasefire agreement and said it is closely monitoring reports of a new column of Russian military equipment moving toward the region. "These aggressive actions and statements by the Russia-backed separatists threaten the most recent ceasefire," the U.S. State Department said in a prepared statement. "We call on Russia and the separatists it backs to halt all attacks immediately." (Reporting by Andy Sullivan)