At least one British army officer is thought to be among five people reportedly abducted by Maoist rebels in Nepal.
The British Army has been recruiting Nepalese men for nearly 200 years
The group were part of a mission to recruit Gurkhas in the remote Baglung region, northwest of the capital, Kathmandu.
Nepalese soldiers were also missing, the district's most senior official said.
Bomb attacks, ambushes and kidnappings have brought the violence to a peak recently, after the rebels pulled out of a seven-month old ceasefire.
The British Embassy would only confirm that a British national was among five men missing in the Baglung district.
If the Maoists are responsible, it will be the first time they have kidnapped foreign nationals.
The rebels are opposed to the recruitment of Gurkhas by Britain and in recent weeks have been involved in several violent attacks aimed at disrupting the process.
More than 8,000 people have died since Maoist guerrillas began an armed struggle to rid Nepal of its monarchy in 1996, the authorities say.
Britain provides non-lethal military aid and training to the Nepalese army as well as much of Nepal's foreign assistance.
A Ministry of Defence spokesman in London could not confirm the officer had been kidnapped, but told the BBC they had lost contact on Sunday night with a team that was observing the recruitment of Gurkhas.
The British Army has been recruiting Nepalese men to fight in its Gurkha brigade for nearly 200 years.
Competition is fierce to join the brigade, which has a reputation for fierce bravery, endurance and loyalty.