One of Mayor Bloomberg’s personal employees was carjacked and assaulted while on an errand for the mayor in New Jersey yesterday.

The employee, who was identified by police as Gradimir Bosnjak, was sitting in Mr. Bloomberg’s 2001 Lexus reading the newspaper when two assailants forced him out of the car and punched him in the face.

According to police in Hackensack, N.J., where the incident occurred, Mr. Bosnjak, 62, fought back and even hung onto one of the suspects as the thieves were speeding away in Mr. Bloomberg’s car around 9 a.m. yesterday morning.

“It’s a coincidence basically that it happened to be the mayor’s car,” the chief of police in Hackensack, Charles Zisa, told The New York Sun. “They had no idea whose car it was.”

Mr. Bosnjak had pulled over on the side of the road in a quiet residential neighborhood where he was to pick up another of Mr. Bloomberg’s employees.

A woman approached the car asking for bus money, creating a decoy that allowed her male counterpart to get into the passenger side of the car, Mr. Zisa said. Once inside, he punched Mr. Bosnjak in the face and the two pushed him out of the vehicle. The suspects did not have weapons and were still at large last night.

According to police, Mr. Bosnjak, who lives in Astoria, Queens, did not go down without a fight. After being forced out of the car, Mr. Bosnjak punched the male attacker several times before the assailant escaped with his accomplice. The commander of the detective bureau of the Hackensack Police Department, Captain Frank Lomia, called Mr. Bosnjak a “steady guy” and said, “he fought him off bravely.”

“This is not something I would recommend to people,” Mr. Lomia said. “But this was a tough guy. He was very concerned about giving up his car, he didn’t want to give up his car.”

The captain said Mr. Bosnjak had bruising under his eye and on his cheekbone, but that he declined medical treatment.

When he arrived at the police station with police he spoke to Mr. Bloomberg on the phone and provided enough information to state troopers to create a sketch of the female assailant.

A spokesman for Mr. Bloomberg, Stuart Loeser, did not identify Mr. Bosnjak by name and said only that he was a “household employee” on a “household errand.”

He said he had the mayor’s permission to be driving the gray Lexus, but would not specify how long he’s worked for Mr. Bloomberg.

Mr. Loeser would not say how many personal employees Mr. Bloomberg, who is a billionaire from his computer information terminal business, has tending to his Upper East Side townhouse, his Westchester County house, and all of his other homes.

He said only that he has “a number” of employees. According to published reports yesterday, the mayor owns nine cars, including three Lexuses.

“The mayor appreciates the Hackensack Police Department’s hard work and hopes that those who committed this crime are swiftly brought to justice,” Mr. Loeser said.

The car was found abandoned about two hours after the incident in downtown Fairlawn, which is about five miles from the Willow Avenue and Herman Street spot where it was stolen.

Mr. Zisa said police watched the car for several hours to see if the assailants would return. When they did not, the car was taken to the Bergen County Sheriff Department and searched for evidence.

Mr. Bosnjack was dropped off at his Astoria apartment in a black Lincoln town car around 6:40 p.m. last night. He was wearing dark sunglasses and a baseball cap. When approached by reporters he said only, “No. I’m tired,” as he walked into his building, a four-story, tan brick tenement. The superintendent in the building said he has been living there for at least 20 years.

Mr. Zisa said carjacking in New Jersey is a first-degree crime that comes with a mandatory five-year prison term and a possibility for up to 30 years.