“We believe an incident has taken place in Afghanistan, as a result of which a UK national is missing,” a British embassy spokeswoman in Kabul told AFP.
“The next of kin have requested that we don’t release the missing person’s name and we are urgently seeking further details from the Afghan authorities,” she said.
The attack took place late on Wednesday on a road linking the western city of Herat with the southern city of Kandahar.
“Taliban militants attacked a Turkish company working on the rebuilding at 5pm yesterday,” said Mohammed Naeem, highway security chief in the western province of Farah.
“A foreigner was kidnapped,” he added, without giving the nationality, adding that three Afghan police escorts were also killed in the attack.
A spokesman for the NATO-led peacekeeping force in Afghanistan said there may have been others abducted, but there are no details of their nationalities.
In March, British development worker Steve MacQueen was shot dead by gunmen as he drove home through Kabul after leaving a bar.
It was unclear if his attackers were Taliban militants or criminals.
Militants and criminal gangs have also kidnapped a string of foreigners in Afghanistan over the past year, including a number of engineers working on construction projects.
A Lebanese engineer was freed by Taliban rebels on August 18 after being held captive for less than a week in the restive southern province of Zabul.
An Italian aid worker was released in May after being kidnapped by a criminal gang in Kabul, however her abduction was not linked to Islamic militants.
Hostage-takers killed a Turkish road worker in December last year in the eastern province of Kunar and three United Nations workers were abducted from Kabul and held for nearly a month before being released unharmed in late 2004.