A close adviser to the commander-in-chief of Ukraine’s army has been killed after a grenade amongst his birthday presents exploded, according to officials, writes The Guardian.

“Under tragic circumstances, my assistant and close friend, Major Gennadiy Chastiakov, was killed … on his birthday”, Gen Valery Zaluzhny posted on Telegram on Monday, saying that an “unknown explosive device detonated in one of his gifts”.

Chastiakov’s death was initially reported as a suspected assassination using a booby-trapped gift until further details emerged. Ukraine’s interior minister, Igor Klymenko, released a statement saying Chastiakov had been showing his son a box with grenades inside that he had received as a gift.

“At first, the son took the munition in his hands and began to turn the ring. Then the serviceman took the grenade away from the child and pulled the ring, causing a tragic explosion”, Klymenko said.

Police had identified a fellow soldier who gave the gift, said Klymenko, and seized two similar grenades. An investigation was under way.

Ukrainian police said the 13-year-old son was also seriously injured. Ukrainska Pravda reported Chastiakov’s wife as saying the grenade was in a gift bag her husband brought home. Some reports suggested the real grenade was amongst novelty gifts shaped to look like grenades.

Chastiakov had left a wife and four children, Klymenko said. Zaluzhny added that since Russia invaded Ukraine in February 2022, Chastiakov had been “fully devoting his life to the armed forces of Ukraine and the fight against Russian aggression”.