The camp, located near Zelenopillya, approximately 40 miles from Lunhansk, was struck by missiles fired from Russian-made rocket launchers.
"According to publicly available information, up to 30 [have been killed]. There might be more victims, because these bloody bastards again meanly shelled [the positions of the Anti-Terrorist Operation forces] with Grad systems, and the destruction there is significant," interior ministry adviser Zorian Shkiriak told reporters in Kiev on Friday.
Shkiriak added the perpetrators would be punished, "either eliminated or captured, and they will answer according to the laws of Ukraine."
Ukraine is in the midst of a military offensive against armed rebels in the eastern region, and recently reclaimed control of Sloviansk and a post along the Russian border. Pro-Russian separatists still control the regional capital of Donetsk, which is being used as their base of operations.