Officials say a suicide bomber has struck outside a private company compound in Afghanistan's western Herat province.

Gunmen battled with Afghan security forces after the Thursday's blast, which happened near a NATO base and Herat's airport.

There was no word on any casualties or who was behind the attack.

In a similar attack Monday, a suicide bomber blew up a car near offices used by the United Nations refugee agency in the southern city Kandahar. Three gunmen then rushed into the area, sparking a gun battle. The Taliban claimed responsibility for the combined attack, which killed five people, including three U.N. employees.

International combat troops are set to complete their withdrawal from the country and transfer full security control to their Afghan counterparts by the end of 2014.