NATO said Sunday three of its service members were killed in southern Afghanistan.

A NATO statement said the first soldier died in an insurgent attack, another one was killed by a roadside bomb and the third died during a military operation.

Also Sunday, a group of suicide bombers attacked a NATO reconstruction base in Qalat, the capital of southern Zabul province, but failed to breach its defenses.

Officials said that one of the assailants blew himself up outside the gate of the base, another one was captured and the third one managed to escape. Two civilians were wounded in the attack.

Elsewhere Sunday, a suicide bomber died during an apparently premature explosion while driving on the outskirts of the capital, Kabul. The blast caused no other casualties.

In northern Afghanistan, a doctor and another medical worker were killed Sunday after their vehicle hit a roadside bomb in Takhar province.