Brussels - NATO and the European Union have both condemned Wednesday's terrorist attack in Kabul, which has left at least six United Nations workers dead.

In a statement, NATO Secretary General Anders Fogh Rasmussen said that by targeting international and Afghan UN staff devoted to helping the Afghan people build better lives, the Taliban had once again demonstrated that they are "truly an enemy of the Afghan people.

The Swedish presidency of the EU issued a separate statement expressing shock at such a "heinous act of terrorism".

"The Presidency expresses its support to the United Nations Assistance Mission in Afghanistan and its solidarity with the mission's staff and their commitment to peace and development.

A total of 12 people were killed when an explosion rocked a guesthouse used by the United Nations in Kabul and armed attackers burst in, sparking a gunbattle in an attack for which the Taliban claimed responsibility.

NATO is present in Afghanistan with more than 71,000 soldiers as part of its International Security Assistance Force (ISAF), which has been mandated by the UN. The EU is also present in the country, providing election monitors and trainers for the Afghan police. (dpa)