An off-duty Mesa police officer and a suspect were killed early Monday morning in a wrong-way collision on a Phoenix-area freeway ramp, the Associated Press reported.

The wrong-way driver's SUV had traveled 35 miles on parts of three freeways for a half-hour before the collision on a ramp connecting Intestate 10 and the U.S. 60 freeway, said Officer Carrick Cook, a state Department of Public Safety spokesman.

Around 12:30 a.m. Monday, calls started coming in about a wrong-way driver cruising on the Loop 101 and Cactus Road in Scottsdale, DPS officers said.

Officers tried to intercept the vehicle as it continued on to State Route 51, DPS spokesman Carrick Cook said. However, the driver eventually got on Interstate 10 and kept on driving the wrong way.

The identity of the wrong-way driver has not been released. He is reported to be a Phoenix man in his early 40s.

Mesa Police Chief Frank Milstead identified the officer who was killed as Brandon Mendoza, 32, and said he was approachable, empathetic and dedicated to his community, working to rehabilitate a park as a community gathering spot, according to the AP.

"Brandon would not be stopped," Milstead said of the park project. "He was everything that a police chief would want an officer to be."

Both Milstead and Cook said Mendoza, who was driving home in his personal car, likely only had seconds of warning before the crash.

"My guess is he was absolutely caught off-guard ... because it is a blind curve and they were coming from different directions at freeway speed," Milstead said.

Preliminary information received from DPS indicated the wrong-way driver was likely impaired, Milstead said. But Cook said it wasn't immediately known whether that's the case or whether the driver was purposely going the wrong way.

At least 12 DPS officers were involved in trying to stop the wrong-way driver, Cook said.

"We were scrambling," Cook said. "Nobody was really pursuing. We were just trying to intercept."