Two British nationals have been detained in the Afghan capital in possession of dozens of AK-47 assault rifles with the serial numbers erased, a government official said on Tuesday.
"Two British nationals along with their two Afghan colleagues, a driver and a interpreter, were today detained carrying 30 AKs. The weapons' registration numbers were removed from them," the official, who requested anonymity as he was not authorised to speak to the media, told AFP.
Kabul police chief Mohammad Ayoub Salangi confirmed that four people had been detained while carrying weapons. He would not disclose their nationality and said the case was under investigation.
The government official who spoke to AFP said the Britons were arrested in an area of Kabul where foreign forces have bases and facilities.
The British embassy said it was "aware of reports that British nationals may have been detained in Kabul".
"Our consular officials in Kabul are in touch with the relevant Afghan police authorities to seek further information," a spokesman told AFP.
Afghanistan is home to thousands of foreign private security personnel providing services for foreign troops, diplomatic missions and aid organisations.
A US congressional report last year found that the number of private security personnel working for the US military in Afghanistan rose to 18,919 at the end of 2010, the highest level used in any conflict by the United States.
Around 95% of them were Afghans, it added.
But relations with the authorities have deteriorated. President Hamid Karzai accuses the firms of breaking the law and taking business away from Afghans.
Perceptions that those working for security firms are little more than gun-toting mercenaries, roaming the countryside with impunity, have made them deeply unpopular among Afghans.