MANAMA (Reuters) - Bahrain is seeking the death penalty for a group of protesters accused of killing two policemen during anti-government demonstrations in the Gulf island kingdom, state media reported Monday. The government has stamped the demonstrations in a security crackdown since February when mainly Shi'ite protesters took to the streets demanding more say in the Sunni-ruled country's affairs. Security forces have arrested hundreds of people since then and a number of them died while in official custody. Hundreds of mostly Shi'ite workers have been sacked from government jobs and state-linked companies, rights and opposition groups say. Sunday, Bahrain News Agency (BNA) said the military prosecutor would seek the death sentence for seven men accused of killing the policemen at the Lower National Safety Court. It quoted the prosecutor as saying the men had "committed their crime for terrorist reasons." It gave no other details of the incident. BNA added the defendants pleaded not guilty and that the case would be heard again on April 28. At least 13 protesters and four police were killed during the clashes. A hospital source told Reuters last month that at least two of the four policemen killed had been run over by cars on March 16. The government says it has only targeted those who committed crimes during the protests. The state banned protests when it imposed martial law in March and invited troops from Sunni-led Gulf neighbours to help quash the unrest. The state news agency said three more men also were charged with attempting to kill policemen in separate court cases.