Sri Lanka's navy destroyed one Tamil Tiger boat and damaged another on Thursday as a battle that produced some of the bloodiest fighting in months raged into a second day on the northwest coast, the military said. The sea battle took place off the fishing port of Nachikkudah, about 300 km (185 miles) north of the capital Colombo, where fighting the day earlier killed 40 Liberation Tigers of Tamil Eelam (LTTE) rebels and 10 soldiers. At least 71 people were killed on Wednesday, one of the deadliest days of combat since Sri Lanka's armed forces intensified a thrust into rebel-held territory three months ago. "There is a sea battle going on in Iranaitivu north sea, at the moment, from the initial reports one LTTE boat was destroyed and another damaged," a naval spokesman said on customary condition of anonymity, referring to the area near Nachikkudah. Nachikkudah has been the scene of heavy fighting for weeks, with ground troops pushing forward and air force jets hitting LTTE bunkers and outposts with almost daily strikes. "Heavy fighting occurred throughout the day on Wednesday and the troops managed to successfully secure an area of 1.5 km of the LTTE's Nachikkudah forward defence line," At least 27 soldiers and 30 rebels were wounded in the fighting. There was no independent confirmation of the casualties and the rebels could not be reached for comment. The rebels' Nachikkudah defences protect the southern flank of Poonaryn, a strategically important spit of land on which the LTTE has artillery batteries that in the past have inflicted heavy casualties on troops crossing the narrow Jaffna Peninsula. Were the military to break through the Jaffna line and push down through the heavily mined area, it would be in a position to strike the LTTE from the north while it hits them on four fronts from the south. Other fighting in the Indian Ocean island nation's north also killed 20 more insurgents and wounded 25 on Wednesday.