Suicide bomb kills seven in southern Afghanistan

(Adds 3rd NATO soldier killed was Czech, paragraphs 1,6)

KANDAHAR, Afghanistan, March 17 (Reuters) - A suicide car bomber killed two Danish and one Czech NATO soldiers, an interpreter and three civilians in southern Afghanistan on Monday, officials said.

The Taliban have threatened to step up their campaign of suicide attacks this year to wear down Afghan and Western public support for the presence of foreign troops in the country.

The bomber attacked a convoy from the NATO-led International Security Assistance Force (ISAF) near the village of Girishk in the southern province of Helmand, an ISAF spokesman said.

"Three ISAF soldiers, one ISAF interpreter and three Afghan civilians were killed by the blast," said spokesman Captain Mark Gough. "Four ISAF soldiers and approximately six Afghan civilians were wounded."

Two Danish soldiers were killed and one was wounded in the attack, the Danish Army Central Command said. The troops were working on a reconstruction project when they were attacked.

The third dead soldier was Czech, as were two of the wounded, the Czech Defence Ministry said.

Most foreign troops in Helmand are British, but another military spokesman said no British soldiers were there at the time. U.S. and Estonian troops are also in Helmand.

Violence has spiralled since the hardline Islamist Taliban relaunched their insurgency to topple the pro-Western Afghan government and eject foreign troops two years ago.

The Taliban rely heavily on suicide and roadside bomb attacks, but as foreign forces use more heavily armed vehicles and are becoming better at avoiding casualties, a greater proportion of the victims are Afghan civilians.

The Taliban carried out more than 140 suicide attacks last year, killing some 200 civilians.

More than 12,000 people, including some 350 foreign soldiers, have been killed in Afghanistan since 2006, according to United Nations estimates.

On Sunday night, a Canadian soldier was killed by an explosion in Kandahar, the ISAF said. (Additional reporting by Martin Dokoupil in Prague) (Reporting by Mirwais Afghan; Writing by Jon Hemming; Editing by Tim Pearce)