Police and bystanders at the scene of the shooting
An Afghan security guard at a courier company in the capital Kabul has shot dead two foreigners and killed himself, the government says.
Two other people were also injured in the incident in front of the DHL office, Interior Minister Mohammed Hanif Atmar told the BBC.
Mr Atmar said the motive for the attack was still unclear, but refused to rule out terrorist activity.
The two dead foreigners were British and South African employees of DHL.
They were killed in front of the DHL office in the Sher Pur area of the city, where many foreign nationals live.
The UK Foreign Office named the dead Briton as David Giles. Confirming the death of two employees, DHL named the second man as South African national Jason Bresler.
DHL has closed its office in Kabul while the police investigate although branches elsewhere in Afghanistan reportedly remain open.
The shooting comes days after foreign aid worker Gayle Williams, 34, who had South African and British nationality, was shot dead in Kabul in an attack reportedly claimed by the Taleban on the grounds that she had been working for a Christian group.
The DHL shooting occurred around 0830 (0400 GMT) on Saturday outside the office on a busy street.
The two foreigners appear to have been killed inside a four-wheel-drive car which stood spattered with blood at the scene. Police later covered it with plastic sheeting.
"So far the investigation shows that the Afghan security guard opened fire and killed the two foreign nationals and then he committed suicide as well," Interior Minister Atmar told BBC World Service's Newshour programme.
Mr Atmar said that investigators were still waiting to interview the two people injured in the shooting but added that the witnesses to the incident had "all confirmed that it was the Afghan security guard who opened fire and then killed himself as well".
Asked about the possible reason for the attack, he said:
"We don't know yet. It could be penetration by the terrorists and it could be other motives."
According to an earlier report, an argument had erupted between the foreigners and some Afghans just before the shooting.
Details of the two injured people were not immediately available.
Phil Malcolm, a friend of Mr Giles, who was 42 and from Hull, described him as "an amazing friend to all who knew him", Britain's Sunday Times newspaper reports.
The dead man's ex-wife, Julia Wilson, with whom he had a 10-year-old son, said from her home in Hull:
"I am just deeply shocked. He is my son's father. I just can't believe what happened."
Tributes to Mr Bresler have appeared on his Facebook page, the newspaper adds.
The BBC's Martin Patience, in Kabul, says that until recently the centre of the Afghan capital has been regarded as relatively safe.
But the latest attacks will raise serious safety concerns, especially among foreigners, our correspondent adds.
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