Robbers armed with a fire extinguisher held up a restaurant in Montgomery County on Thursday night, carrying out the third extinguisher robbery in the same general area in a week.

News accounts from around the country have occasionally cited other robberies in which extinguishers have been brandished, discharged or used as blunt objects to inflict injury.

In Thursday’s incident, the robbers discharged an extinguisher inside El Meson restaurant in the 600 block of S. Frederick Avenue, the county police said.

One of the robbers grabbed the cash register and both men ran, the police said. They were being sought Friday night.

Capt. Paul Starks, a county police spokesman, on Friday night confirmed a television news report describing two robberies involving an extinguisher that were carried out in Gaithersburg on Jan. 12.

According to the account, robbery victims were sprayed with an extinguisher before items were taken from them. Four people were picked up, but it was not clear that charges were brought.

The robberies, which were investigated by Gaithersburg police, were reported within a mile or so of the Thursday night incident.