Montreal police investigating a string of firebombings at cafés and businesses have found links to Italian organized crime in more than half the recent incidents.

At a press conference Tuesday afternoon, police announced that a new task force is looking into the dozens of arson attacks and has already made four arrests, with more expected.

Commander Mario Lamothe of Montreal police speaks at a news conference on Tuesday. (CBC)Project Impact investigators have made 140 visits to cafés and bars, visits which also led to the arrests of 21 individuals for possession of drugs.

Cmdr. Mario Lamothe, the head of Montreal police's arson and economic crime squad, said 19 Italian business have been targeted in recent months, and all of them have something in common.

"The illegal activity that is going there, drugs basically. It can be illegal gambling, it can be prostitution, and the known organized crime figures, that's a common aspect," said Lamothe.

Montrealers have seen a barrage of firebombings all over the city in recent months. (CBC)The arson attacks are part of a turf war among Italian crime organizations, he said.

The firebombings in Montreal began in the spring and have elevated in frequency since late summer. Most of the incidents have occurred in the city's north and northeast boroughs.

Chantal Rouleau, the mayor of the Montreal borough Riviere-des-Prairies/Pointe-aux Trembles, said the three arson attacks in her community this past month have citizens on alert.

"Citizens are certainly worried by what is happening. So many events is worrisome," she said.

View an interactive map of the recent surge of arson incidents in Montreal below

View Montreal firebombings in a larger map