A suicide bomber rammed an explosives-laden vehicle into a checkpoint in a neighborhood housing United Nations and international aid groups' offices and guest houses in the southern city of Kandahar early Monday, killing four people including an Afghan policeman, Afghan officials said.
Security forces were exchanging fire with armed insurgents who rushed into the area and seized control of a building, Kandahar police chief Gen Abdul Razzaq said.
Nato said that Afghan security forces were "leading the efforts against the attackers."
Immediately after the 6:15 am bomb attack, several insurgents rushed into the area and seized control of an animal clinic near the office of the International Relief and Development organization, said Faisal Khan, head of the Kandahar local government media office.
The clinic and IRD offices are near guest houses affiliated with both the IRD and the UN refugee agency, UNHCR, he said.
The area is also home to several other international NGO offices and guest houses.
The Taliban claimed responsibility for the attack, with spokesman Qari Youssef saying the insurgents were targeting what he claimed was a guest house affiliated with the United Nations Assistance Mission in Afghanistan. But UNAMA does not operate a guest house in the area.
Earlier reports said three security guards in the area were killed, but Mohammad Faisal, spokesman for the Kandahar governor's office, said three civilians and one policeman were killed. Three civilians and a Nepalese guard were wounded, said Faisal.
UNAMA said it was aware of the situation, but that "all our staff, both Afghan and non-Afghan ... have been accounted for," said agency spokesman Dan McNorton.
The attack comes two days after the Taliban launched a brazen midday suicide bombing in Kabul, striking a Nato convoy on Saturday and killing 17 people, including five Nato service members, eight civilian contractors and four Afghans.