when Sri Lankan armed forces drove the Liberation Tigers of Tamil Eelam from the northern Jaffna peninsula earlier this year, it was a major military triumph for the government of President Chandrika Kumaratunga. The Tigers, as they are known, retreated into dense jungles southwest of Jaffna, losing their operational headquarters and the territory they had occupied for most of their 13-year war to secure an independent homeland for Sri Lanka's minority Tamil population.

The government, however, learned last week that tigers in the jungle can still be fearsome. At 1:30 a.m. Thursday, more than 1,000 guerrillas surrounded a Sri Lankan Army camp at Mullaitivu on the island nation's northern coast. Half came from the forest and the rest from the sea. The army was evidently unprepared for a major assault, and the Tigers quickly got past defensive bunkers. They proceeded straight to the base's communication center and blew it up, toppling a radio tower. Simultaneously, they raided the armory, distributed arms for the ongoing assault and sending other weapons, including artillery pieces, back to the L.T.T.E. base 10 km away. The battle for the camp continued through the weekend. The navy managed to sink several Tiger vessels and to protect the camp from the sea but lost a fast attack craft in the battle. The Tigers controlled the jungle, cutting the base off from overland reinforcements. In the first 40 hours of fighting, as many as 400 government troops were feared killed.

In Colombo, Sri Lanka's capital, officials were grudging with details of the attack on the 1,000-strong garrison. They were plainly stunned by the Tigers' show of strength. After retaking Jaffna town in December and clearing the entire peninsula of the L.T.T.E. in May, the government considered the group incapable of a major offensive. Kumaratunaga had announced plans to rebuild Jaffna and continue efforts to push her proposals to share power with the Tamils through Parliament. But the L.T.T.E., who are proficient in both jungle warfare and assassinations--they killed India's former Prime Minister Rajiv Gandhi--showed again that underestimation is the group's best ally.

Some Colombo analysts concluded that the military made a strategic blunder in capturing Jaffna peninsula before it controlled the forests of northern Sri Lanka around Mullaitivu, where the Tigers were certain to take refuge. But the government saw the same merit in reconquering the peninsula as the Tigers and their leader Velupillai Prabhaharan did in holding it: Jaffna is the center of Tamil culture in Sri Lanka and the core of what Prabakharan longs to make an independent country. "Jaffna is called the head," says a senior military analyst. "Maybe we should have gone for the heart first."

--Reported by Kendall Hopman/Colombo