At least six people, including two Americans, have been killed in a suicide attack in southern Afghanistan, officials and witnesses say.
Reports say a suicide bomber blew himself up in front of a security company building in Kandahar - a Taleban stronghold.
A number of people were injured in the attack, officials said.
Correspondents say there are now so many attacks in Kandahar it is nicknamed "bomb city" by many Afghans.
Both Nato and US-led troops are stationed in the province.
The bomber attacked the men as they came out of the building, company official Rohullah Khan told the Associated Press news agency.
The dead men - two Americans and four Afghans - were working for the company.
The area where the attack happened is close to a place where Canadian troops are based in Kandahar.
The BBC's Mark Dummett in Kabul says there has been a wave of suicide attacks in Kandahar this week - Wednesday's incident was the sixth suicide attack in Kandahar province in the last eight days.
On Tuesday, two civilians were killed and at least three others wounded when a suicide bomber attacked a Nato convoy by driving a car laden with explosives into their vehicles.
On Sunday, a suicide car bomber struck near a British convoy in Kandahar city - three Afghans were killed and three British Royal marines were injured.
There has been a wave of suicide attacks in Kandahar
In a separate incident, UK forces said that one British marine had died during a 10-hour battle with the Taleban in the Helmand province.
A reporter travelling with the British forces said the marines were forced to fall back from Gamser town, which continues to be held by the Taleban.
This year Afghanistan has plunged into the bloodiest period of violence since US-led troops overthrew the Taleban's radical Islamic government in 2001.
The fiercest fighting has been in the south of the country.
Nato says that since 1 January 2006, about 227 Afghans and 17 foreign troops have been killed by suicide bombers.