Villagers look at paddy fields that dried up after Tamil Tiger rebels cut off water, in Trincomalee, Tuesday

Officials in Sri Lanka say Tamil rebels have launched new attacks in the country's volatile northeast, as the island appears to be falling back into full-scale civil war.

Government forces also renewed strikes Thursday against Tamil rebels, mainly in and around the northeastern district of Trincomalee.

On Wednesday, 40 rebels were killed in fighting, along with five members of the Sri Lankan military and two civilians.

The rebels say they have overrun four government outposts in Trincomalee, but military officials say the insurgents have not gained any territory.

Fighting has been intense in the area, where rebels last week cut water supplies to more than 12,000 hectares of farmland and a community of 50,000 people.

A senior envoy from Norway, which mediated the cease-fire agreement, is expected in Sri Lanka later this week to try to salvage a 2002 cease-fire agreement.

At least 850 people have died this year in sporadic clashes, as the ceasefire meant to end two decades of fighting has steadily unraveled.

The rebels, officially known as the Liberation Tigers of Tamil Eelam, or LTTE, are fighting for a separate homeland for the ethnic-minority Tamils, who say they are oppressed by the country's Sinhalese majority.

Some information for this report was provided by AP and Reuters.