Assailants have shot and wounded three opposition supporters who were preparing a stage for President Mahinda Rajapakse's chief rival on the final day of campaigning in Sri Lanka's election, police have said.

The men were hit in a drive-by shooting as they erected a podium for Maithripala Sirisena to address a rally in the southern town of Kahawatte, around 130 kilometres from the capital Colombo, on Monday.

"We have information about the identity of attackers and we are trying to make arrest," police chief Ajith Rohana said.

A nearby ruling party office was attacked shortly after the shooting in what appeared to be a retaliatory strike, Rohana added.

Sporadic violence was reported from other parts of the island, prompting Sirisena to appeal for calm as the campaign was due to end at midnight.

"I have conducted a peaceful campaign and appeal to my opponent (Rajapakse) to please also ensure that there is peace in the three days before the voting on January 8," Sirisena told reporters in Colombo.

He said he was confident of victory and promised protection for Rajapakse and his family members in what he called a "new post-election political culture I will usher in from Friday".

The ruling party has also expressed confidence of winning the election that the incumbent called two years ahead of schedule.

Rajapakse, who oversaw Sri Lanka's 2009 victory over Tamil separatist rebels at the end of a 37-year ethnic conflict, had been seen as the overwhelming favourite at the start of the campaign.

But he has been undermined by defections from both within his party and other members of his ruling coalition, throwing into doubt his prospects of winning an unprecedented third term and extending a nine-year rule.

Source: Al Jazeera