A basement fire in the Roma Restaurant interrupted dinner for several dozen customers Thursday evening.

The sprinkler system did its job and kept the blaze from causing more extensive damage, according to Deputy Fire Chief Eric Tarpy. Employees and diners left the 29 Middlesex St. restaurant quickly and there were no injuries, Tarpy said.

It was too soon Thursday night to say whether the popular restaurant, a fixture in Haverhill for more than 50 years that specializes in Italian cuisine, would be able to reopen, Tarpy said. City inspectors will assess the situation, he said.

The fire was reported at 7:33 p.m. Engine 3, from the main station on Water Street, was the first to arrive and firefighters encountered heavy smoke in the kitchen, Tarpy said. A thermal imaging camera helped firefighters get to the source of the fire in the basement, he said.

They hooked up a line to a hydrant located in front of the Roma and doused the fire. Firefighters then went to work ventilating the building.

An alarm at the restaurant alerted the Fire Department, Tarpy said. Telephone callers also reported the fire, he said. The single-alarm blaze brought a full response from the city’s firefighting force. Besides Engine 3, Engines 2, 4 and 5, Ladder 1 went to the scene. Three Trinity ambulances also responded.

Companies from Groveland, Lawrence and Methuen provided coverage at the 16th Street, High Street and Water Street stations while Haverhill firefighters were deployed to the Roma. Salem, New Hampshire sent its ladder truck.

Many of the diners and employees went to the parking lot across the street from the restaurant. Daniel Stanford, who has been a cook at the Roma for six years, said it appeared the compressor on an ice machine in the basement caught fire.

The sprinklers activated quickly and doused the fire, he said, but it still produced thick, black smoke.

Sharyn Linzey, of Haverhill, a regular customer at the Roma, said she had just finished eating a pizza when the smoke alarms went off. Employees ordered “everybody out!” she said.

“I didn’t get to finish my soda,” she said. “I hope they reopen tomorrow (Friday) because they have karaoke at 9.”

Terry Connolly and his wife Peggy were sitting at the bar sipping wine, waiting for dinner.

“Her salad had just come out. Next thing I know, the alarms go off,” Terry said. He never did get to enjoy his garden salad with chicken, he added.

The Connollys, of Haverhill, have been regular customers at the Roma for many years. They generally eat there once a week, they said.

“Everybody was good about getting out,” Terry said.

Fire engines began leaving the scene by around 9 p.m.