Miscreants attacked two TMC activists and opened fire in the air outside one of the ruling party's offices in the northern outskirts of Calcutta, triggering panic in the area, a police officer said on Sunday.

Six persons have been arrested so far in connection with the incident, he said.

"At least 10-12 motorcycle-borne men arrived at the TMC's Deshpriyonagar zonal party office in North 24 Parganas around 9.30 pm on Saturday, ransacked the furniture there and dragged two TMC activists out before hitting them with the butt of a revolver," the officer explained.

They then fired a few shots in the air and fled the place, leaving the two injured activists lying on the road, he said, adding that locals are wary of stepping out of homes.

The incident, meanwhile, has sparked a furore, with the TMC holding BJP workers responsible for the attack, a charge denied by the saffron camp.

"The BJP, after its poll debacle, is desperately trying to terrorise TMC workers. We will take out a rally in in protest," local MLA Madan Mitra, who visited the site of the incident during the day, told reporters.

State BJP president Dilip Ghosh, however, claimed that the attack was a fallout of infighting in the TMC, with two factions seeking to have total control over the real estate sector in the area.

Meanwhile, in yet another incident, TMC MLA Lovely Moitra alleged that a pandal built for a public outreach programme in her Sonarpur Dakshin constituency was "set on fire" late on Saturday.

"Some rogue elements are trying to sabotage our programmes in the area. They will not succeed," Moitra said, further adding that the police are probing the matter.