Deputy Commissioner (headquarters), Howrah police commissionerate, Ajit Singh Yadav was among the injured, officials said.

Sources said the demonstration was on since the afternoon in Purba Para of South Sankrail.

Personnel form Sankrail police station went to the spot and tried to pacify the demonstrators, who hurled bombs at the security forces in the evening, injuring the three cops.

The police then went for a baton charge, which further infuriated the protestors, who started raining stones and bottles at the lawkeepers.

Some other policemen also sustained minor injuries.

The injured were taken to the Sankrail police station for preliminary treatment.

The area was tense with the streets deserted except for the police personnel on patrol duty.