Sri Lanka's air force bombed a well-fortified Tamil Tiger rebel compound in their northern stronghold on Saturday, while a rebel ambush killed a policeman in the east, the military said. Pilots said the bombing of the compound in Kilinochchi district was successful, the military said. It gave no details of damage or casualties. Meanwhile, rebels attacked a police guard post in eastern Batticaloa district on Saturday, killing one policeman, the military said in a statement. Sporadic clashes Friday along the northern front lines killed nine Tamil Tigers and one soldier, it added. With most of the lines of communication to the north cut, it was not possible to reach rebel officials for comment. It is difficult to verify statements by either side because most journalists are banned from the war zone. The government has increased its attacks on the Tamil Tigers' northern stronghold in recent months and has seized a number of rebel camps and villages. The government and international aid groups began working on Friday on a deal to deliver emergency food aid to 160,000 civilians displaced by Sri Lanka's raging civil war in the wake of a ban on relief agencies in rebel-held areas. Aid groups and UN agencies have already begun to withdraw their staff and equipment from the northern areas under Tamil Tiger control, though they have expressed concern that many will starve as a result of the government's order that humanitarian groups leave the war zone. An aid official said Friday's meeting ended without a decision on the major issue of how to ensure that aid continues to flow into the conflict area, but that the two sides would meet again to discuss it. The government has agreed to allow local staff to stay to assist with the distribution of stocks left behind, said the official, who spoke on condition of anonymity because he thought the government should announce the results of the discussion.