Trincomalee, Sri Lanka, May 11: Sri Lanka's ruling coalition was Sunday declared the winner of key elections in the east of the island, and hailed its victory as a major boost for the war against Tamil rebels.

Election officials confirmed the governing United People's Freedom Alliance party (UPFA) and its allies had won control over a new 35-member provincial council in the eastern coastal region.

Opposition parties and monitoring rights groups, however, complained of widespread irregularities, including harassment by Tamil Tiger defectors now allied to hawkish President Mahinda Rajapakse.

Rajapakse hailed the vote as 'a clear mandate for peace through the defeat of terrorism, the strengthening of democracy and the development of the country.'

The region, once home to several Tamil Tiger enclaves, was brought under government control after heavy fighting last year, and Colombo is determined to show normality has returned.

The polls were overshadowed by the rebel sinking of a navy cargo ship in Trincomalee port hours before voting started on Saturday, as well as a bomb attack in the town of Ampara late Friday that killed 12 civilians.

But the government boasted that the Liberation Tigers of Tamil Eelam (LTTE), who are fighting for a separate state in the north and east, had suffered a major blow by failing to derail the elections.

'The government victory at the eastern polls has shattered the wild dreams of the West-backed Eelamists,' or Tamil separatists, said Sri Lanka's environment minister, Patali Champika Ranawaka.

'The verdict of the people is that they are happy with the government's ongoing strategy to defeat separatism,' added Susil Premajayantha, a senior government official and education minister.

The result, he said, gave the government a mandate to step up the war against the LTTE, who are now hemmed in to a swathe of jungle in the north.

The president wants to partially devolve power in the east from his ethnic Sinhalese-dominated government to ethnic Tamil allies in the Tamil People's Liberation Tigers (TMVP), a grouping of LTTE defectors.

The government pulled out of a truce with the rebels in January, but says the polls prove it is serious about addressing Tamil grievances and undermine the LTTE's contention that Colombo is racist.

The polls were the first to be held in the tsunami-hit and ethnically-mixed eastern districts of Batticaloa, Trincomalee and Ampara in 20 years.

With all votes counted, election officials said Rajapakse's ruling UPFA and its TMVP allies had won 20 out of 35 council seats up for grabs.

Another two seats will be awarded to the winning party for a total of 37.

But the opposition UPA party, allied with the Sri Lanka Muslim Congress (SLMC), complained of widespread irregularities.

'We don't accept the results. In Batticaloa and Ampara, the government with the TMVP rigged the votes, especially in Tamil-dominated areas. We are collecting the evidence,' said SLMC leader Rauf Hakeem.