Colombo - Three sailors and four rebels were killed Tuesday when Tamil separatist guerillas and the Navy clashed on an island off north-western Sri Lanka, a military spokesman said.

The rebels arrived in six boats and mounted an attack on a Navy guard point at Erukkalampiddi on Mannar island, 320 kilometres north of Colombo, he said. Sailors fought back, repelled the attack and also sought air support to attack the fleeing rebels, the spokesman said.

The incident came as government troops pushed further into rebel-controlled areas in the Mannar district, which includes the island, in military operations that have lasted more than six months.

The rebels, who are seeking an independent state for minority Tamils in majority-Sinhalese Sri Lanka, have been putting up resistance, but troops have been able to push back the guerillas and take control of some previously rebel-held areas.

The government has vowed to retake all rebel-controlled areas in the north by the end of the year.

Nearly a year ago, security forces had taken control of rebel-held areas in eastern Sri Lanka, the Tamils' other stronghold, and held local elections there in May.

Since the renewal of fighting in 2005, more than 5,000 rebels, security forces personnel and civilians have been killed.

A Norwegian-brokered ceasefire was in place from February 2002, but after fighting recommenced, the truce was ignored by the two sides, and eventually, the government officially pulled out of the agreement in January this year. (dpa)