At least four Ukrainian soldiers died after a grenade exploded during training in northern Ukraine, The National Bureau of Investigation (DBR) reports this on Monday.

The incident took place in the Chernigov region on Saturday, the DBR said in a statement on Telegram. Authorities have opened an investigation for “violation of gun handling rules”, same source added.

The bodies of the four soldiers were transferred to Chernigov is being examined by a forensic teamhe continued, without elaborating.

The Chernigov region borders Russia and Belarus and was partially occupied by Moscow during the first weeks of the invasion in late February 2022.

Since the withdrawal of Russian troops from this region in the spring of 2022, the Kyiv army closely monitors every movement of the Moscow forces in the north of Ukraine, especially in Belarus.