On a Russian military firing range near Ukraine on Saturday, two men opened fire on soldiers, killing 11 and injuring 15, before being killed themselves, according to the Russian Defense Ministry.

The incident happened in the southwest Russian region of Belgorod, which borders Ukraine, according to a statement from the ministry. It said that during target practise, two men from an undisclosed former Soviet republic opened fire on volunteer soldiers and were killed in retaliation.

Also read: Elon Musk on Starlink: We’ll just keep funding Ukraine government for free

The incident was classified as a terrorist attack by the Russian Ministry.

The incident happens as President Vladimir Putin hastily mobilises Russian military in Ukraine, an action that sparked riots and forced hundreds of thousands to escape Russia.

In an effort to recruit 300,000 more reservists, Putin stated on Friday that more than 220,000 have already been called up. He assured them that the mobilisation would end in two weeks.

Also read: US firm supplied IT equipment to sanctioned Russian missile maker: Reports

In a nation where practically all men under the age of 65 are designated as reservists, officials gave conflicting instructions on who should be called up for service, making the mobilisation problematic from the outset.

Despite the Russian president’s declaration that only those who had recently served in the military would be called up, activists and rights organisations reported that military conscription offices were rounding up individuals without any prior military experience, some of whom were also medically unfit for duty.

Also read: Elon Musk denies having spoken to Vladimir Putin, says met Russian president once

Some of the recently activated reservists uploaded recordings showing themselves being given rusted weapons and made to sleep on the ground or even outside before being sent to the front lines.

According to Russian media accounts, some of the mobilised individuals were pushed into battle without the required training and were promptly murdered.

Authorities acknowledged that the mobilisation was frequently disorganised and pledged to make changes.