A Russian general who was wanted by Ukraine for using chemical munitions was killed by a remotely detonated bomb in Moscow on Tuesday, Russian authorities said.

Lieutenant General Igor Kirillov, who oversaw Russia’s nuclear, biological and chemical protection forces, was killed by an explosive device planted in an electric scooter outside an apartment building some 7 km (4 miles) southeast of the Kremlin, according to Russia’s investigative committee.

Kirillov’s assistant was also killed in the blast, the committee added, describing it as a “terrorist act.”

A criminal investigation into the deaths is underway, the committee said, adding that investigators, forensic experts and operational services are working at the scene.

“Investigative actions and operational search activities are being carried out to establish all the circumstances of the crime,” the committee said.

Videos posted on Russian Telegram channels showed emergency service officers walking outside a shattered entrance to a building littered with rubble, while two bodies lay in the snow.

The power of the explosive device, which was detonated remotely, amounted to some 300 grams of TNT, Russian state news agency TASS reported.

The site of the explosion has been cordoned off, according to TASS.

Kirillov’s death came a day after Ukrainian prosecutors charged the general in absentia with the use of banned chemical weapons in the war on Ukraine. According to the Security Service of Ukraine, more than 4,800 cases of Russian use of chemical munitions have been recorded on Kirillov’s orders since the beginning of the war.

Kirillov had also been sanctioned by Britain for the “abhorrent use of inhumane chemical weapons” on the battlefield in Ukraine.

In a statement announcing the sanctions in October, the UK foreign office said Kirillov was “responsible for helping deploy these barbaric weapons.” It also accused the general of being “a significant mouthpiece for Kremlin disinformation” and “spreading lies to mask Russia’s shameful and dangerous behavior.”

This is a developing story and will be updated.