Afghan officials say suicide bombers killed at least four private Afghan security guards and wounded 10 others in the capital of northern Kunduz province.

The officials say one suicide bomber detonated his explosives-laden car just before dawn Tuesday outside a compound in Kunduz city that houses two separate private security companies.

Two other militants stormed the facility, triggering a gunbattle with police. The fighting ended when the militants inside the building detonated their explosives. Officials said foreign nationals staying at the complex were able to escape.

The Taliban claimed responsibility for the attack, the first major strike by insurgents in Afghanistan since the beginning of the Muslim holy month of Ramadan.

Afghanistan's Interior Ministry condemned the assault in Kunduz “in the strongest terms.”

Elsewhere, NATO said one of its service members was killed in a bomb blast in eastern Afghanistan.

Meanwhile, the director-general of the U.N. Educational, Scientific and Cultural Organization , Irina Bokova, condemned the killing of an Afghan journalist in last month's Taliban attack in the capital of southern Uruzgan province.

In a statement Tuesday, Bokova said “the death of a journalist in the line of duty is a loss for a country striving for democracy and rule of law.” She said she was deeply concerned about continuing violence and loss of innocent lives in the war-torn country.

Ahmad Omed Khpalwak was among at least 19 people killed in the assault on the governor's house and police headquarters in Tarin Kot. The British Broadcasting Corporation said the 25-year-old journalist was one of its part-time reporters.

According to the Institute for the Protection of Journalists, Khpalwak is the first Afghan journalist killed this year.