Britain's Foreign Office on Sunday urged its nationals to leave the self-declared nation of Somaliland, warning of a "specific" threat against Westerners in the northern Somali region.
Britain had similarly warned of a "specific and imminent threat to Westerners" in the eastern Libyan city of Benghazi on Thursday and urged its citizens to leave, swiftly followed by Germany, the Netherlands, Australia and France.
The Foreign Office said it already advises against all travel to war-torn Somalia including Somaliland -- a rare area of relative stability -- but now urged any remaining citizens to pull out.
"We are now aware of a specific threat to Westerners in Somaliland, and urge any British nationals who remain there against our advice to leave immediately," the ministry said in a statement.
"As our travel advice continues to make clear, kidnapping for financial or political gain, motivated by criminality or terrorism, remains a threat throughout Somalia."
A Foreign Office spokesman declined to give an estimate of how many British citizens were currently in Somaliland.
"There are quite a lot of people who have dual Somali and British nationality who travel back and forward to the area, as well as a number of NGOs operating in Somaliland," he told AFP.
While anarchic southern Somalia has been riven by years of fighting between multiple militia forces, the former British protectorate of Somaliland has enjoyed relative peace.
It won independence from Britain in 1960 but days later joined with Somalia. In 1991, after years of bitter war with the government in Mogadishu, it declared independence from the rest of the country.