Says their network is being run from AfghanistanPolice in Karachi claimed to have arrested six suspected militants on an intelligence tip-off, a senior police official said Saturday.Fida Hussain Janwari, the West SSP, told reporters that the arrested men were planning a big terrorist attack in Karachi.“The arrested terrorists were involved in attacks on the Army, Frontier and levies Constabulary in various parts of Balochistan in the past,” the police official said. “They carried out terror attacks on check-posts and have confessed.”Karachi stock exchange attack: Sindh Rangers say four terrorists killedThe police official said that the arrested men have admitted that they belong to separatist BRAS organization. Baloch Raji Ajoi Sangar or BRAS is a coalition of Baloch separatist armed groups.The authorities have beefed up security in Karachi after the June 29 attack on the Pakistan Stock Exchange. The militants had killed three people, including a police official, in an attack on the stock exchange last month. All four militants were killed by the police during the encounter.Why young, educated Baloch are joining separatist groups?The West SSP claimed that the arrested men have confessed to receiving training and financial support from the Indian intelligence agency.Their network is being run from Afghanistan, he added.