Colombo: Sri Lankan jets hit the Tamil Tiger frontline on Friday as fighting raged on the northern Jaffna peninsula, cut off by the rebels, and residents with foreign passports begged their embassies to get them out.

Almost three weeks of ground fighting, the first since a 2002 ceasefire, has left the government-held Jaffna enclave largely cut off and areas near the port of Trincomalee under intermittent artillery fire.

"In Jaffna, it's becoming almost a First World War type of battle," said a Western diplomat. "They are sitting in the ground shooting at each other without much real movement."

The military said it had bombed selected targets on the front line where the two sides have now been fighting for a week. Communication with the area is virtually impossible, with curfews in most civilian areas and shortages rising.

Across the island, the United Nations High Commissioner for Refugees (UNHCR) says more than 160,000 people have fled their homes 41,000 of them in Jaffna.

Aid staff say there are queues for fuel, shortages of food and a desperate scramble to get cash from banks whenever the curfew is lifted for a few hours.

Fearing robbery as crime rose along with violence between government and rebels earlier in the year, many Jaffna residents sold their jewellery and valuables and put their money in banks. Getting access to it is now almost impossible, aid staff say.

"We need both sides to stop fighting so we can get proper access to the area," said UNHCR representative Amin Awad. "Food is getting low and we have worries about water and sanitation."