Updated at 12:45 p.m. ET

A lone gunman opened fire near the headquarters of the FSB, Russia's Federal Security Service, on Thursday night, killing at least one person before authorities were able to "neutralize" the attacker, according to reports.

The incident took place within hours of Russian President Vladimir Putin's annual news conference.

Multiple eyewitness reports said the gunfire came from near the main FSB building — formerly the KGB — on Lubyanka Square. The location is a short distance from the Kremlin.

There are conflicting reports about the number of casualties and the number of shooters involved.

Authorities say the gunman was "neutralized" and two FSB officers seriously wounded, according to RT.

Meanwhile, the newswire service Interfax says one FSB officer was killed in the gunfire by a lone gunman. The attacker did not manage to get into the heavily fortified building.

The incident reportedly took place in a parking area which police quickly cordoned off.

Local news outlet Baza posted a tweet showing video of what it says are the initial shots of the attack, captured by surveillance cameras.

"Panic among passers-by, drivers abandon their cars and run away. Police officers, hiding behind the cars, pulling themselves to the place of shooting," the tweet reads in Russian.

Several videos show people running down a dark street as gunfire rings in the background.

Reuters reports that witnesses say five ambulances left the scene of the shooting.

Others said Russia special forces armed with "automatic weapons have been deployed to the scene."

This is a breaking news story. Some things reported by the media will later turn out to be wrong. We will focus on reports from officials and other authorities, credible news outlets and reporters who are at the scene. We will update as the situation develops.

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