COLOMBO (AFP) - Clashes between Sri Lankan soldiers and rebels left 17 dead in the country's war-ravaged north, while a suicide attack on Sunday killed one civilian, the defence ministry said. Nine people were also injured in the suicide blast targeting police officers in the town of Vavuniya, the ministry said, blaming the attack on Tamil Tiger rebels. Four police and three soldiers were among the wounded, it said. Elsewhere in the north, troops killed 12 rebels on Saturday, while five soldiers also died in clashes, the ministry said. The Liberation Tigers of Tamil Eelam (LTTE) made no comment on the fighting. Sri Lankan troops are close to capturing the rebels' political capital of The United Nations on Sunday said it would begin sending food convoys to Kilinochchi and Mullaittivu, after Sri Lanka ordered aid workers out of the region in the face of the heavy fighting. Mohamed Saleheen, head of the UN's World Food Programme in Sri Lanka, said 60 trucks would enter the rebel-held areas within days to deliver badly needed supplies to some 230,000 displaced civilians. Colombo relaxed its stand after UN Secretary General Ban Ki-moon expressed concern about civilians during talks with Sri Lankan President Mahinda Rajapakse in New York last week. The latest wave of fighting has killed at least 6,983 rebels, according to the ministry, which admits losing 682 soldiers in the same period.