KABUL, Afghanistan (AP) — A teenage suicide bomber blew himself up outside NATO headquarters in the Afghan capital today, killing at least six civilians in a strike that targeted the heart of the US-led military operation in the country, officials said.

The Taliban claimed responsibility for the blast, which was the latest in a series of insurgent attacks in the heavily-fortified Afghan capital aimed at undercutting a months-long campaign by the US-led coalition to shore up security in Kabul before a significant withdrawal of combat troops limits American options.

While bombings and shootings elsewhere in Afghanistan often receive relatively little attention, attacks in the capital score propaganda points for the insurgents by throwing doubt on the government's ability to provide security even the seat of its power. The attacks also aim to undermine coalition claims of improving security ahead of the planned withdrawal of foreign troops by the end of 2014.

The bomber struck just before noon Afghan time outside the headquarters of the US-led NATO coalition, on a street that connects the alliance headquarters to the nearby US and Italian embassies, a large US military base and the Afghan Defence Ministry.

The alliance and police said all of the dead were Afghans, and the Ministry of Interior said some were street children. Kabul police said in a statement that the bomber was 14 years old.

The Taliban claimed responsibility for the attack, saying the target was a US intelligence facility nearby.