Two British contractors were among 13 people killed when a suicide bomber rammed a military convoy in Afghanistan, the Foreign Office said.
Five coalition troops and eight civilian contractors were killed in the Kabul attack on Saturday, Nato said.
The Taliban suicide bomber hit an armoured Nato vehicle as the convoy was passing the American University in the city.
A Foreign Office spokesman said: "Two British nationals were among those killed in yesterday's attack in Kabul. Next of kin have been informed.
"Consular staff in Kabul are in close contact with the employer of the deceased. Our thoughts are with the families of those who died, ISAF personnel, contractors, Afghan forces and civilians.
"We stand ready to provide the consular assistance needed to their families."
The armoured personnel carrier, known as a Rhino, was travelling on a four-lane road frequently used by Nato forces in a south-western section of the city.
In addition to those killed in the convoy, three Afghan civilians and one policeman died as a result of the attack. Eight other Afghans, including two children, were wounded, officials said.
Many of the attacks in Kabul have been blamed on the Haqqani network, an al Qaida and Taliban-linked movement that operates out of Pakistan.
The UK is set to withdraw its combat troops from Afghanistan in 2014.