Imphal, Nov 1 : Security forces fired in the air in the Manipur capital on Wednesday evening to disperse a mob agitating since Tuesday against the killing of a Sub-Divisional Police Officer (SDPO) by suspected militants at Moreh in Manipur's Tengnoupal district bordering Myanmar. A police official said that a large number of men and women have been agitating in Imphal and other places after the suspected militants on Tuesday gunned down SDPO Chingtham Anand Kumar at Moreh, 110 km south of Imphal. The mob clashed with the security forces and reportedly attempted to besiege the 1st Manipur Rifles complex, close to the Raj Bhavan and Chief Minister's Office in Imphal West district, demanding arms and ammunition. "To control the mob, the security forces first carried out a baton charge and then opened fire in the air. Few civilians sustained minor injuries in the clash," the official said. The Imphal West District administration, in view of the tense situation in the capital, cancelled the relaxation periods of the curfew. The district administration, like previous days, has relaxed the curfew from 5 a.m. to 10.p.m.. In a separate incident on Tuesday, three policemen sustained bullet injuries when suspected militants fired on a convoy of the state force at Sinam in Tengnoupal district. The convoy was sent to Moreh as reinforcement to assist in conducting combing operations after the killing of the SDPO. Demanding arrest and punishment of the militants, the mob also asked the government to deploy more state forces in Moreh and arrest the militants operating in the area bordering Myanmar. During the protest rally, the agitators held several placards and shouted slogans demanding authorities to take swift action against the militants and change the leaders of the unified command. /IANS