Four NATO soldiers have been killed in new attacks in Afghanistan, including a Taliban suicide bomb yesterday that also took the lives of three Afghan civilians, security forces say.

Two Danes, a Canadian and a Czech with the International Security Assistance Force (ISAF) were killed in the violence in the south of the country, which sees the worst of a Taliban-led insurgency.

A suicide car bomb ripped into an ISAF convoy as it was travelling on the main road linking the southern city of Kandahar with Herat in the west, a witness said.

Three ISAF soldiers were killed and four wounded in the attack in Helmand province, the alliance force media office in Kabul said, revising an earlier death toll of four.

ISAF does not release the nationalities of its casualties but the Danish military said two of its troops were killed and one injured.

The soldiers were from a Danish unit that works on reconstruction projects, it said.

The Czech military said separately one of its soldiers was also killed.

Helmand police chief Mohammad Hussain Andiwal said three Afghan men were killed in the blast, near a bazaar in the town of Girishk, and seven were wounded.

"It was a busy hour of the day when everyone was going to their work," Mr Andiwal said.

Taliban claim the attack

One of the Taliban's main spokesmen, Yousuf Ahmadi, confirmed the attack was carried out by a fighter from the extremist militia, which was in government between 1996 and 2001.

Helmand is perhaps the most volatile province in Afghanistan and the prime producer of the country's opium and heroin output, which in part funds the insurgency.

In another incident announced Monday, a Canadian soldier died in an explosion Sunday while on foot patrol in Kandahar province, which neighbours Helmand, the Canadian military said.

The incident took place in Panjwayi, about 35 kilometres west of Kandahar, which has seen intense clashes between security forces and Taliban although it has been fairly quiet in recent months.

Meanwhile two rebels were killed in a clash after insurgents attacked government officers in Western Herat province on Monday, the authorities said.

The deputy intelligence chief of neighbouring Badghis province survived unhurt in the attack, but two other officers were wounded, a statement by the intelligence department said.

The Taliban was ousted from power in late 2001 in a US-led offensive because it did not hand over its Al-Qaeda allies after the September 11 attacks on the United States.

They are waging a bloody insurgency which saw more than 160 suicide attacks in 2007, the deadliest year of their campaign with more than 8,000 people killed, according to the United Nations.