Six Russian soldiers were killed in a firefight in a shelter in his area Kurskwhich borders Ukraine, he said the Russian Ministry of Defense in a statement cited by Russian news agencies.

The fire broke out near the village of Ulanok, which is located less than 10 kilometers from the southeast of Ukraine with Russia, the TASS agency reported this morning, citing emergency services.

The Russian Ministry of Defense reported that the fire was the result of “gross trespass” of security rules, without presenting further details, Ria Novosti agency reported.

The Baza channel on the Telegram app, which is close to law enforcement agencies, reported that an explosion occurred in a shelter. Reuters could not immediately confirm the report.

Seven soldiers were inside the bunker at the time of the accident, emergency services said. The six died while the seventh person was injured.