The violence continued unabated despite the steps taken to appease Tamil sentiments, such as the 13th Amendment (enacted in November 1987). Meanwhile, the Chief Minister of the then North and East Provincial Council, Vartharaja Perumal, put forward a 19-point demand to resolve the ethnic crisis. He threatened if these demands were not met that the Provincial Council would go ahead with a unilateral declaration of independence of the northern and eastern provinces, as in the case of Rhodesia. President Premadasa moved to quickly dissolve the Council (March 1990). At the same time LTTE used terror tactics to scare Sinhalese and Muslim farmers away from the north and east of the island, and swiftly took control of a significant portion of the territory. When the Indian Peace-Keeping Force withdrew in 1989–90, the LTTE established many government-like functions in the areas under its control. A tentative cease-fire held in 1990 as the LTTE occupied itself with destroying rival Tamil groups while the government cracked down on the JVP uprising with the Operation Combine. When both major combatants had established their power bases, they turned on each other and the cease-fire broke down. The government then launched an offensive and tried to retake Jaffna but failed.