Exterior of Comet Ping Pong photographed in Washington, DC. (Photo by Deb Lindsey For The Washington Post).

D.C. Police responding Sunday to a report of a gunman at a popular pizza restaurant in Northwest Washington detained a man armed with an assault rifle, according to a police spokeswoman. 

Police received a call about a man with a weapon a just before 3 p.m., said Aquita Brown, a spokeswoman for the department. Officers responded to the scene at Comet Ping Pong, a pizza restaurant on Connecticut Avenue with ping-pong tables that is popular with families.

She said there were no reports of injuries and no shots fired.

It’s not clear what motivated the suspect in Sunday’s incident. The restaurant, however, was swept up in the onslaught of fake news that was prevalent during the presidential campaign.

The restaurant’s owner and employees were threatened on social media in the days before the election, the New York Times reported, after fake news stories circulated claiming that then-Democratic presidential nominee Hillary Clinton and her campaign chief were running a child sex ring from the restaurant’s back rooms. None of it was true, but the fake stories and threats persisted, some even aimed at the employees’ children.

The restaurant’s owner was forced to contact the FBI, local police, Facebook and other social media platforms in an effort to remove the articles.

On Sunday, Gareth Wade, 47, and Doug Clarke, 50, were sitting down for pizza and beer at Comet when they spotted a commotion. All of a sudden, said Wade, “the server said someone just walked in with a shotgun.”

They rushed out of the restaurant and had planned to walk to Politics and Prose, the bookstore across the street, where Clarke’s wife and five-year-old son were browsing.

They were met by a heavy police presence.

“Police said you can’t go to the bookstore,” Wade said. They ended up behind the police barricade at Connecticut Avenue and Fessenden Street. Clarke’s wife and son were forced to remain inside the bookstore.

[Fake news makes Comet Ping Pong a target for conspiracy theories]

On social media, some people reported an armed man.