Seventeen people, including 12 schoolchildren, have been killed in a suicide bombing in south Afghanistan, the country's interior ministry says.

Another 30 people were injured, some seriously, in the attack on a market place in Dehrawood in Uruzgan province, where Taleban militants are active.

The bomber blew himself up near a Nato-led convoy, police said.

The Nato-led international force (Isaf) said seven of its soldiers were among the injured.

If the death toll is confirmed, this would be the third deadliest bomb attack in Afghanistan this year, says the BBC's Charles Haviland in Kabul.

Many children were caught in the explosion as they were leaving classes near a crowded bazaar in Dehrawood.

A Nato spokesman told the BBC he believed more than a dozen people had been killed and that Isaf troops were among the wounded.

The wounded were all being treated at an Isaf medical centre. Some of them were said to be in a serious condition.

Isaf had earlier said that at least six people had been killed in the attack.

The Nato spokesman said the attack showed a "wanton disregard" for the safety of civilians. The bombing contradicted recent public calls by fighters that civilian casualties should be avoided, he said.

Isaf has not given the nationalities of its injured troops, but most of its contingent in Uruzgan comes from The Netherlands.

Heavy fighting

Less than a month ago, another suicide attack in the same province killed at least 10 people including a Dutch soldier.

More than 6,000 people have died in resistance-related violence in the past 18 months.

Uruzgan was also the scene of heavy fighting last month between Afghan and foreign forces on the one hand and Taleban fighters on the other.

About 90 foreign troops have been killed in Afghanistan this year, most in combat for the Nato-led military force Isaf in the country's south.

Correspondents say the south of the country this year has seen the worst violence since the Taleban were ousted from power in 2001 by a US-led international coalition.

PHOTO CAPTION

An Afghan boy receives treatment after the bombing