Colombo - Tamil Tiger rebels began an offensive aimed at capturing Jaffna city yesterday, hours after their offer of a temporary ceasefire was rejected by the Sri Lankan government. President Chandrika Kumaratunga has ruled out any evacuation of the 40,000 troops marooned in Jaffna by the rebel advance. She said: "We will not allow the half-million people of Jaffna to fall into the hands and the fascist rule of the Liberation Tigers of Tamil Eelam."