A U.S. Capitol Police officer stands his post as a bright sunrise and sub-freezing temperatures greets lawmakers returning to work on Jan. 5, 2016. (J. Scott Applewhite/AP)

The U.S. Capitol Police on Wednesday suspended the use of the department’s newly refurbished indoor firearms range in the Rayburn House Office building, a move the union said was taken because bullets fired at targets were bouncing back toward officers.

Jim Konczos, chairman of the labor committee representing police officers assigned to the Capitol Hill force, said the range has been the subject of complaints since it reopened less than a month ago. The nine-lane facility is in the basement of the House building on Independence Avenue SW.

Konczos said one officer was slightly injured last week when a bullet fragment ricocheted and struck him in the corner of one eye. Police officials said they were unaware of any injuries at the range, and Konczos said the officer had not reported it because it was minor.

Capitol Police Chief Kim Dine would not describe the problem leading to the closure, but said upgrades to the gun range were to make it modern and state-of-the-art, as well as to improve safety features. “Obviously the safety of our officers is paramount, and any kinks or issues that need to be worked out will certainly be accomplished,” the chief said.

News of the closure came in a news release from the U.S. Capitol Police attributing the closure to “operational concerns.” The statement says the closure is temporary until “range designers identify and examine those concerns.”

A spokeswoman for the Capitol Police, Tasha M. Jamerson, described the problem as a “design issue” that is being investigated. She declined to elaborate. Jamerson did say that the decision to close the range was made “out of the utmost caution.”

A spokesman for the sergeant at arms, the chief law enforcement and protocol officer for the House of Representatives, referred questions to the Capitol Police.

The identity of the contractor or contractors who handled the gun range renovations and how much it cost could not immediately be determined on Wednesday. Laura R. Condeluci, a spokeswoman for the Architect of the Capitol, did not address that question in an email response and instead said only that her office is “aware of the issues with the firing range and are working with contractors to resolve them.”

Konczos said it as yet unclear where Capitol Police officers will be able to practice firing their guns, which is necessary to pass proficiency tests given every six months. He said they could make provisions to use the Federal Law Enforcement Training Center in Southern Maryland.

The union head said that problems with the new range started almost immediately. He said that “as officers shot down range, bullets or fragments ricocheted and were coming back at them.”

He said officials told officers that “they did a run-through of the new range and told us it was safe. . . . I’m disappointed that the department was aware of this and they continued to operate the range.”

But once police officials closed the facility, Konczos emailed them to say he appreciated that they took the precaution to address the officers’ concerns.

Jamerson said officials closed the range as soon as problems were brought to their attention. Roll Call said the gun range has been in the building for 50 years.