European countries urged their nationals to leave the eastern Libyan city of Benghazi today, with Britain citing a "specific and imminent" threat to Westerners days after a deadly attack by Islamist militants in neighbouring Algeria.
Officials declined to give details, but Britain has warned of a growing militant threat in North Africa, which Prime Minister David Cameron has called a "magnet for jihadists".
The call to leave Libya's second largest city irked Libyans keen to win foreign investment to rebuild a fractured infrastructure and boost the oil industry after the revolution which toppled Muammar Gadafy in 2011.
"We are now aware of a specific and imminent threat to Westerners in Benghazi, and urge any British nationals who remain there against our advice to leave immediately," the foreign office said in a statement.
Similar warnings came from Germany and the Netherlands.
They followed the deaths of at least 38 hostages in an attack on Algeria's In Amenas gas complex near the Libyan border, and the start of French military operations in Mali.
German foreign minister Guido Westerwelle described the situation in Benghazi, cradle of the uprising against Gadafy, as "serious and delicate".
"The warning was made because of a series of bits of information. We have our reasons, but I would not like to speak of details. Security is the most important thing," he told reporters during a visit to Lisbon.
Few Westerners are believed to be in Benghazi, which has experienced a wave of violence against diplomats as well as military and police officers, including an attack in September that killed the US ambassador and three other Americans.
A British embassy spokeswoman in Tripoli said the number of Britons in Benghazi was small, without specifying further.
Libyan deputy interior minister Omar al-Khadrawi said there were no more than 20 British nationals in Benghazi and most worked at international schools.
Last week Italy suspended activity at its Benghazi consulate and withdrew staff after a gun attack on its consul.
"The situation in Cyrenaica (eastern Libya) is not just worrying, it is incredibly worrying," a Western diplomat said. "But in light of the events recently, this could be a precautionary measure."
With the country awash with weapons and its shaky nascent institutions struggling to rein in armed groups, Libyans are keen to ensure Western fears do not drag down its economy.
The bulk of Libya's oil wealth, around 80 per cent, is located in the east of the country, but the oil installations are far from Benghazi and oil is not piped through there.
"The British ambassador told me about this decision yesterday and I told him to give me reasons for this fear, and he said we have threats and fears for our people there. I asked him for something written, and he still hasn't provided it," deputy interior minister Khadrawi told Reuters.
"They have the right to be fearful for their people and it is our duty to protect them and our citizens. The threats they are speaking of, we are taking seriously. The British decision should have been taken together with the Libyan government."
Mr Cameron's spokesman batted away accusations that Britain's warnings undermined confidence in Libya after Gaddafi and said that "progress can, is being made in Libya".