KUNDUZ, Afghanistan: Three people, including a German security guard, were killed Friday when suicide bombers and gunmen stormed the compound of a US aid organization in northern Afghanistan in an attack claimed by the Taliban.

At least four suicide bombers attacked the premises of Development Alternatives Inc (DAI) in Kunduz city and two detonated their explosive vests, Mohammad Omar, the governor of northern Kunduz province, told AFP.

Smoke billowed from the building, which was surrounded by NATO-led Afghan troops after the latest strike by insurgents against foreign targets in the nearly nine-year conflict.

“The first suicide attacker detonated at the entrance, the second detonated inside the premises, killing one foreign national,” he said, adding that one security guard and one policeman were also killed.

Two of the attackers were killed by security forces before they were able to detonate their explosives, he said, while two militants were “still resisting” from inside the compound.

An official at the US embassy in Kabul said a German security guard was killed and that another foreigner, whose nationality was not immediately clear, had been shot in the arm as expatriates fled on to the roof.

Both German and US troops are based in Kunduz under ISAF’s operations to quell an intensifying Taliban insurgency.

A Taliban spokesman claimed responsibility for the attack, which began around dawn.

“This morning six Taliban suicide bombers attacked the United States development organisation branch,” Zabihullah Mujahid told AFP by telephone from an undisclosed location.

Northern Afghanistan has largely escaped the violence that blights the southern provinces, mainly because the population is dominated by Tajiks and Uzbeks, rather than the Pashtuns who make up the bulk of the Taliban.

In the past year, however, violence in the region has escalated as the Taliban converge on road routes that bring supplies from Central Asia to military bases in Afghanistan.

DAI is a so-called “implementing partner” of Washington’s international aid arm USAID. It is believed to have opened its Kunduz operation about four months ago.

Such contractors are playing an increasingly important role in Afghanistan, utilising billions of dollars in aid money pouring into the impoverished country in an effort to rebuild after 30 years of war.

A spokesman for NATO’s International Security Assistance Force (ISAF) said Afghan and foreign troops were involved in the clearing operation and had been evacuating the injured.

The Taliban are stepping up attacks on foreign targets in reaction to intensified efforts by the US and NATO to rout the militants, particularly from their strongholds in the south of the country.

Friday’s attack came just days after Taliban gunmen attacked a major NATO base in the eastern city of Jalalabad, setting off a car bomb and firing rockets.

It was the latest in a series of attacks on military bases, although many do come under regular rocket fire.

US aid contractors have been attacked in a number of locations in Afghanistan in recent months, notably in the southern provinces of Helmand and Kandahar where fighting is fiercest.

Suicide and gun attacks on foreign firms — most involved in delivering aid projects — have shaken the companies and hampered their efforts to recruit foreign staff as part of the “civilian surge” to speed development.

The US and NATO have 140,000 troops in Afghanistan, with most of the newly-deployed heading to the south as part of a US-led counter-insurgency strategy aimed at bringing the fight to the Taliban.

NATO also said Friday that one of its soldiers had been killed in eastern Afghanistan, bringing the death toll so far this year to 324.