KABUL, May 23: Eleven Taliban fighters and three policemen were killed when guerillas attacked a convoy of provincial officials in southern Afghanistan, the government said on Tuesday. In a separate incident, a roadside blast west of Kabul killed four Afghan aid workers, police said.

The attacks come after several days of some of the heaviest Taliban attacks since they were ousted in 2001 and just as NATO is bringing thousands of extra troops into the country.

More than 250 people have been killed since last Wednesday, according to figures from the US military and Afghan authorities.

Most of the dead were militants but dozens of Afghan policemen, soldiers and civilians have also been killed, along with four foreign soldiers.

President Hamid Karzai ordered an investigation into the killing of 16 civilians in air strikes during an attack by US-led forces on Taliban in Kandahar on Monday.

The government convoy in Helmand, which included the provincial police chief, was travelling in the north of the province when it came under attack late on Monday.

“Three policemen were martyred and six were wounded,” said Interior Ministry spokesman Yousuf Stanizai. Eleven Taliban were killed in subsequent fighting, his ministry said.

A Taliban spokesman, Qari Mohammad Yousuf, claimed responsibility for the attack and said there were no Taliban casualties.

The police chief in Maidan-Wardak province west of Kabul, Subhan Qul, said four Afghan aid workers, one of them a woman, were killed when a roadside bomb hit their vehicle on Monday.

An official at an agency overseeing security for aid workers said the four dead were a doctor, two nurses and a driver.

The Taliban, fighting to expel foreign forces and defeat the western-backed government, have attacked and killed aid workers in the past, accusing them of supporting the government.

CIVILIANS KILLED: Authorities in Kandahar said that 16 civilians were killed in bombing by US-led forces after Taliban took up positions in their homes. Some villagers said the toll was higher.—Reuters