KIEV, Ukraine 

At least five Ukrainian soldiers have been killed in clashes with pro-Russian separatists in eastern Ukraine, according to Ukraine's spokesperson for the National Security and Defense Council.

Andrey Lysenko said  on Wednesday at least five soldiers were killed and 12 wounded in clashes and an explosion in eastern Ukraine, and claimed pro-Russians had violated the Feb. 12 Minsk cease-fire agreement 42 times in the last 24 hours and used heavy weapons.

The situation in Donetsk and Mariupol regions was very tense and clashes were continuing, he added.

The cease-fire agreement includes the withdrawal of heavy weaponry from combat areas, the withdrawal of all foreign-armed formations and release of all hostages and unlawfully detained persons, as well as political reforms and decentralization in the eastern Ukrainian regions.

More than 6,000 people have lost their lives in the conflict between Ukrainian forces and pro-Russian separatists since April 2014, according to the U.N.