An angry crowd beat a D.C. firefighter Sunday who authorities say may have been intoxicated or under the influence of drugs when he arrived at an emergency call for an injured child, according to police and fire officials.

A spokesman for the D.C. fire department said the 34-year-old firefighter, a 10-year veteran, is the subject of an internal investigation.

He is assigned to Engine 30, near the Marshall Heights neighborhood in Southeast Washington. The firefighter also is an emergency medical technician, and on Sunday, he had been assigned to Ambulance 30. Officials were not able say whether he had been driving.

No one was arrested. Two witnesses to the Sunday afternoon attack described a crowd surrounding the firefighter “but could not give a lookout” on the assailants, according to the police report.

The firefighter suffered a broken jaw and was in a hospital Monday. A department spokesman said surgery is scheduled for Tuesday. The firefighter could not be reached for comment.

The incident began with a call about 1 p.m. to an apartment in the 200 block of 37th Street SE, just north of Fort Dupont Park, to treat a 3-year-old child who had fallen inside an apartment and was injured.

According to a police report, the firefighter offered to treat the child but the “parents refused because they felt [he] was inebriated.”

The firefighter and his partner returned to the ambulance, where the attack occurred, police said.

The injured child was taken to a hospital in a different ambulance and was treated for what officials described as minor injuries. The child’s mother declined to comment Monday.

The fire department issued a statement that said: “At some point Sunday afternoon, while still on the scene, allegations were made that the member who was assaulted was possibly intoxicated or under the influence of drugs.” The statement added that the firefighter “is now the subject of a comprehensive internal review.”