Sri Lanka's four-year ceasefire is over,a top Tamil Tiger said on Monday as fighting between the guerrillas and the military entered its sixth consecutive day.

S. Elilan, head of the Tigers' political branch in the eastern district of Trincomalee, told the Reuters news agency the two-decade civil war has started again.

Recent months have seen a sharp increase in violence, including a bus bombing that killed 60 people and the assassination of a senior Sri Lankan army officer.

Sri Lanka's civil war pits the Tamil Tigers, who seek a separate homeland for ethnic Tamils in the north and east of the country, against the majority Sinhalese community.

Simmering ethnic tensions exploded in the early 1980s and the ensuing civil war was one of the bloodiest in Asia.Peace talks between the sides stalled in 2003.

With files from Reuters