UNITED NATIONS, November 7. /TASS/. The UN Children’s Fund (UNICEF) offered its condolences over the death of two children in shelling of a Donetsk school and reminded all parties to the conflict that they should protect civilians.

“UNICEF is saddened to learn that at least two children were killed and four have been injured as a result of shelling of a school sports field in Donetsk city on 5 November 2014,” says a statement received by TASS. “We at UNICEF express our deepest sympathies to the families of the children who have lost their lives or been injured. UNICEF reminds all parties to the conflict that they have a responsibility to keep children out of harm’s way.”

UN Under-Secretary General for Humanitarian Affairs Valerie Amos wrote on her Twitter account on Thursday: “Am very concerned by reports of shelling near Donetsk school... Children and other civilians bearing the brunt of this senseless violence.”

On Thursday Russia’s Investigative Committee said that it opened a criminal case on the deadly shelling of a Donetsk school. The investigators say that on Wednesday afternoon servicemen of the Ukraine’s Armed Forces and National Guards opened fire from artillery weapons upon their commanders’ orders targeting School 63 in Donetsk.

The head of the self-proclaimed Donetsk People's Republic, Alexander Zakharchenko, signed a decree on Thursday declaring November 6 and 7 the days of mourning over two teenagers killed in the shelling.