KANDAHAR (Afghanistan) - A ROADSIDE bomb struck a tractor carrying people to a wedding in southern Afghanistan, killing 21 civilians in one of the deadliest strikes in weeks, Afghan officials said on Thursday.

The attack, which took place on Wednesday but was not reported until Thursday morning, was part of a mounting wave of violence two weeks before Afghans go to the polls for a presidential election.

General Sher Mohammad Zazai, commander of an Afghan military unit in Helmand province, said the explosion happened in Garmsir, a district of the province where US Marines launched the biggest operation of the war last month against Taleban militants.

'It's the work of the enemy of the nation, it's the work of the enemy of peace and the work of the Taliban,' he said.

Assadullah Sherzad, police chief of Helmand province, said by telephone that the dead included women and children, heading to a wedding in a trailor pulled by a tractor.

Defence Ministry spokesman Zaher Azimi confirmed the incident and the death toll, as did the Interior Ministry in a statement, which said five other civilians were wounded.

A spokesman for the US Marines in the area, First Lieutenant Abraham Sipe, said he was checking the report.

A separate roadside bomb exploded next to a police vehicle on Thursday in another part of Helmand province, the Nad Ali district, killing five policemen and wounding three others, the Interior Ministry said in a statement.

Last month US and British forces launched simultaneous major operations in Helmand province, and they are still fighting to secure areas previously held by Taleban insurgents.

In another incident, a US soldier was killed by a roadside bomb in the western province of Farah while on patrol on Wednesday, the US military said. At least 71 international troops were killed in July, the worst monthly toll for foreign forces since the start of the war. -- REUTERS