KIEV, Dec. 29 - Two Ukrainian soldiers were killed and two others injured in 24 hours in attacks by pro-Russian separatists in eastern Ukraine, a security official said Thursday.

"Two Ukrainian soldiers lost their lives and two others were injured during a military operation in the last 24 hours," said Alexander Motuzyanik from Ukraine's Anti-Terrorist Division.

Motuzyanik said although a cease-fire entered into effect at midnight Dec. 24, it was violated 15 times in Lugansk and Donetsk regions.