(CNN) -- Taliban militants attacked the compound of a U.S. aid agency subcontractor in northern Afghanistan early Friday, killing at least four people and wounding 20 others, government officials said.
The pre-dawn raid started when a suicide bomber on foot and another in a car detonated at the gate of the compound, said Kunduz Gov. Mohammad Omar. Following the initial assault, four gunmen stormed the facility, firing machine guns and throwing hand grenades, according Omar.
The attack was on an office of DAI, a humanitarian assistance subcontractor working with USAID.
The Taliban said the building was a base for U.S. special operations troops, a claim the U.S. military denied.
Two Afghan security guards and two foreigners died in the attack, said Abdul Raziq Yaqubi, the Kunduz police chief.
In a conflicting report, Taliban spokesman Zabiullah Mujahid said six militant gunmen had killed nearly all of the 52 foreigners at the compound.
The fighting came as Gen. David Petraeus, the new U.S. military commander in Afghanistan, is due to arrive in Afghanistan Friday.
"The attack by insurgents in Kunduz was an attempt to intimidate Afghans and members of the international community trying to improve the lives of all Afghans," said a statement from NATO's International Assistance Security Force, condemning the attack.
"This attack shows the insurgents' desire to prevent progress and draws attention to their true goal of serving themselves rather than the people of Afghanistan," said Navy Capt. Jane Campbell, an ISAF spokeswoman. "We remain committed to serving alongside our Afghan partners to improve security and development for all Afghans".
