MENDENHALL, Miss. (AP) — At least three people died and four were critically injured after a Mississippi bridge, in the process of being demolished, collapsed Wednesday afternoon while work was being conducted at the site, authorities said.

The deaths and injuries were confirmed by Simpson County Sheriff Paul Mullins, WLBT-TV reported.

The Simpson County coroner’s office was responding to the scene but did not provide any additional details, WJTV-TV said.

The Mississippi Department of Transportation, in a news release, said the bridge over the Strong River on State Route 149 in Simpson County, about 40 miles (64 kilometers) south of Jackson, has been closed to traffic since Sept. 18 as part of a bridge replacement project handled by contractor T.L. Wallace Construction.

Details of how the accident occurred were not immediately available.

The Associated Press left phone messages for Mullins and the Simpson County coroner, Terry Tutor. A call to the construction company was unanswered Wednesday evening, and it was not possible to leave a message.

Department of Transportation spokesperson Anna Ehrgott said the agency “would share more information with the public as it becomes available.” The department said one of its inspectors was at the work site when the bridge collapsed, and that person was unharmed.