Phoenix police were investigating after a suspected impaired driver collided with a Phoenix firetruck early Sunday morning, injuring five firefighters, officials said.

Just before 1 a.m. Sunday, officers responded to the area of 75th Avenue and Thomas Road after reports of the collision, authorities said in a statement.

Police said that five firefighters and the driver of the other vehicle were taken to a hospital as a “precaution,” with Phoenix fire officials adding that all involved were taken in “serious but stable condition.”

Four of the five firefighters have since been released from the hospital, with the fifth in stable condition, officials said.

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Through the course of the investigation, police stated the driver of the other vehicle, later identified as 30-year-old Alexis Mendoza, showed signs of impairment. Preliminary information, according to police, indicated Mendoza ran a red light and collided into the firetruck while it was en route to a call.

Officials would not say as to what incident the Phoenix firetruck was responding to.

Mendoza was ultimately arrested and booked into a Maricopa County jail, and he is facing one count of driving while impaired, police said.

No other information was released as the investigation remained ongoing.

This article originally appeared on Arizona Republic: Firetruck collision: police investigate potential drunk driving crash