COLOMBO • Unidentified gunmen opened fire at an election campaign rally in the Sri Lankan capital Colombo yesterday, killing a woman and wounding at least 12 people, police said.

The attackers sprayed bullets into the crowd just after Finance Minister Ravi Karunanayake left the venue, marking the first major outbreak of violence ahead of the Aug 17 parliamentary elections.

Police spokesman Ruwan Gunasekera said: "The gunmen travelled in two vehicles and escaped in the same vehicles after the shooting spree. A woman was killed and 12 wounded persons have been admitted to the Colombo National Hospital." Hospital sources said two of the victims were in a "very critical" condition.

Investigators cordoned off the Bloemendhal area, where the shooting took place, and launched a search for the two getaway vehicles, Mr Gunasekera said.

Deputy Minister of Policy Planning, Dr Harsha de Silva, expressed shock and vowed not to allow a return to violence. "I'm in shock and in disbelief at the shooting incident at Ravi's event," Dr de Silva said on Twitter.

"No one will be allowed to reverse what we achieved on Jan 8," he added, referring to the election of new President Maithripala Sirisena, who ousted Mr Mahinda Rajapaksa from the job after a decade in power. Critics said his authoritarian regime was marred by nepotism and corruption.

Mr Karunanayake, 52, is from the ruling United National Party (UNP), which backed Mr Sirisena in January's presidential election.

Soon after taking office, Mr Sirisena invited the UNP to form a minority government after he sacked the Rajapaksa administration.

Election monitors also expressed surprise at the shooting in Colombo, where security is tight and campaigning has been mostly peaceful.

Some 70 international election observers are monitoring the campaign ahead of polling this month.

Mr Keerthi Tennakoon, head of the Campaign for Free and Fair Elections (CaFFE), said: "We are puzzled by this latest turn of events in Colombo because, so far, it has been relatively calm, and even the level of violence in other areas has been very low."

CaFFE said there had been about 55 clashes since Mr Sirisena dissolved Parliament on June 26 and called for a general election, nearly a year ahead of schedule.

This month's election will be the first since a recent constitutional amendment gave the commissioner greater powers to run the process independently.

Almost all previous elections were marred by allegations that government workers colluded with the party in power to give them an undue advantage in the polls.

AGENCE FRANCE-PRESSE, REUTERS