A suicide bomber detonated explosives outside of NATO headquarters in Kabul killing six civilians including children on Saturday, according to NATO and local officials.

The bomber arrived at the gates of the NATO facility on his bicycle Saturday morning before detonating the bomb in the busy area. Afghan police say the bomber was 14 years old.

The Taliban has claimed responsibility for the attack, but denies the bomber was a teenager.

Tensions are high in the city this week as NATO increased its security presence in the streets of Kabul ahead celebrations of the 11th anniversary of the death of Ahmad Shah Massoud, the hero of the 1980s war against Soviet forces, and opponent of the Taliban.

Saturday's bombing is only the latest in a spate of violence within the country, which spiked in the months of July and August, revealing continued insecurity in the war torn region.

Concerns of vulnerability to 'insider' and 'green on blue' attacks as well as a spike in suicide bombings in busy areas have brought attention to NATO's failed mission of improving security ahead of a planned withdrawal of foreign troops by the end of 2014.