A 2006 District ambulance truck erupted into flames Tuesday morning outside of an apartment building while it was responding to an emergency call on Benning Road SE, a fire department spokesman confirmed.

The cause of the fire is still unknown, though it appears from a picture that the District of Columbia Firefighters Association posted on Twitter that the engine caught fire. The patient the emergency responders were scheduled to pick up was not in the vehicle at the time and was transported by another vehicle. Although there were no reported injuries, the incident represents the latest in a string of problems for the city’s ambulance fleet.

Last Thursday a D.C. ambulance on presidential motorcade duties was relegated to the South Lawn after it ran out of gas because its fuel gauge was broken, the Washington Times reported Monday.

And during last month’s scorching heat waves, so many of the city’s ambulances were sent to mechanics that the city had to rent out ambulances from private companies for special events like a Nats game.

These incidents come just months after the city launched an investigation into the  fire department for not having any readily available ambulances to transport a seriously injured police officer in Southeast. City Paper reported in March that at the time of the emergency call, four ambulances were out of service for mechanical reasons. The District is supposed to have 39 ambulances available to report to emergency calls at any given time.

“The incident this morning is an indication that the department has aging vehicles in its inventory,” D.C. fire department spokesman Timothy Wilson wrote in an email. “We have devised a plan that should aggressively replace our aging fleet.”

A spokesman for the Deputy Mayor for Public Safety and Justice said Tuesday that the city is planning on having a press conference later this month “releasing good news on that front.”