An unidentified assailant detonated an explosive device next to a patrol vehicle in Moscow on Tuesday, killing himself and a police officer in an apparent suicide bombing, according to The Associated Press. 

The outlet noted that, according to officials, the explosion also left two other officers injured.

The attack happened just after midnight on Tuesday near the Savyolovsky railway station in downtown Moscow, according to RUSSIA’S WAR AGAINST UKRAINE ENTERS FIFTH YEAR AS EXPERTS OUTLINE 3 POSSIBLE OUTCOMES

The attacker reportedly approached traffic police officers who were sitting in a patrol vehicle, PUTIN PUTS ‘NUCLEAR TRIAD’ ON FAST TRACK, ZELENSKYY CLAIMS ‘WORLD WAR 3’ UNDERWAY

Russian President Vladimir Putin allegedly said at a meeting with top officials from Russia’s Federal Security Service (FSB) that the young man was recruited online and was unknowingly given an explosive device that was then detonated remotely, according to the AP.

The attack came just as Russia marked the fourth anniversary of its invasion of Ukraine. While the Trump administration has worked to broker a peace deal between the two sides, Putin and Ukrainian President Volodymyr Zelenskyy have yet to reach an agreement.

The Associated Press contributed to this report.