Air force helicopters Monday bombed a Tamil Tiger rebel position in northern Sri Lanka, a day after ground clashes around the rebel stronghold killed 21 insurgents and a soldier, military said. A military statement said that the air force targeted a rebel point in Andankulam village of northern Mannar district to back up the infantry operations. It did not identify the rebel location nor release details of damages. Ground fighting on Sunday were reported from Jaffna, Vavuniya, Mannar and Welioya regions, the military said. Rebel spokesman Rasiah Ilanthirayan could not be reached immediately for comment and it was not possible to get independent accounts of the violence because reporters are not allowed in the war zone. Both sides are known to exaggerate casualties inflicted upon their enemy while lowering their own damages. Fighting has raged around the rebel defacto state in the north for the past several months with soldiers trying to break into the territory from four fronts. Encouraged by its military success last year, when the insurgents were driven away from their eastern strongholds, the government has vowed to crush the rebels by the end of this year. The Tamil Tigers have been fighting since 1983 for an independent homeland for minority ethnic Tamils, who have been marginalized for decades by governments dominated by the Sinhalese majority. More than 70,000 people have been killed in the fighting.