The police force tasked with protecting Congress said it is conducting an investigation after Rep. Andy Harris, R-Md., set off a metal detector when he tried to carry a concealed weapon into the Capitol building.

The Washington Post on Friday reported that Harris was patted down after setting off the magnetometer near the House chamber. The metal detector was installed after the Jan. 6 breach of the Capitol building.

“One security official present saw a firearm on the person of Rep. Harris and relayed that to his superiors,” a staffer said in a text message sent to the Post on condition of anonymity. “To be clear, Harris did not enter the Floor.”

A statement from Capitol Police to the newspaper said only that it was “ investigating the matter.”

WBBF, a Fox affiliate in Baltimore, carried a statement from a Harris spokesperson, saying the Republican lawmaker was concerned for his personal safety.

“Because his and his family's lives have been threatened by someone who has been released awaiting trial, for security reasons, the Congressman never confirms whether he nor anyone else he's with are carrying a firearm for self-defense,” the statement read. “As a matter of public record, he has a Maryland Handgun Permit. And the congressman always complies with the House metal detectors and wanding. The Congressman has never carried a firearm on the House floor.”

Harris is among the handful of Republican lawmakers facing calls to step down for thier support of false claims of election fraud. A non-partisan group, Common Cause Maryland, called on Harris to resign for his decision to voice opposition to results in the Electoral College that confirmed Joe Biden as the 46th president.

Harris is among the members of the GOP who spread disinformation about the election results that led to unrest at the federal Capitol building on Jan. 6, the group alleged.

Last week, CNN carried several statements from Republican lawmakers outraged over the new security measures on Capitol Hill. Freshman Rep. Lauren Boebert pledged to arm herself inside the Capitol building, while Oklahoma Rep. Markwayne Mullion said it was a “constitutional right” to bear arms.

Boebert, a backer of the far-right QAnon conspiracy theory, is facing fines after she was allegedly disarmed by Capitol security.

Washington D.C. has strict gun laws, including prohibitions on any weapon that can carry more than ten rounds of ammunition.

Handguns for sale at Coliseum Gun Traders Ltd. in Uniondale, New York
Handguns for sale at Coliseum Gun Traders Ltd. in Uniondale, New York AFP / TIMOTHY A. CLARY