A number of British women travelling with an aid convoy are believed to have been raped in Libya.
Pro-government militiamen are suspected of attacking three of the activists in the eastern city of Benghazi, the country's deputy prime minister Awsad al-Barassi said.
The women were reportedly kidnapped on Tuesday and later released.
Mr al-Barassi told a Libyan television channel he had met the women and they were in "very bad shape".
A Foreign Office spokesman said: "We are aware of an incident in Libya involving a number of British nationals who were part of an aid convoy.
"We are providing consular assistance."
Huseyin Oruc of IHH, a Turkish humanitarian relief organisation which mediated the release of the kidnapped group, said the women were attacked and robbed.
Their alleged abductors included a taxi driver and a group of men in military uniforms, he said.
The attack is the latest in a series of violent assaults on aid agencies and diplomatic missions in the region where authorities have been battling to provide security since Muammar Gaddafi was overthrown in 2011.
Benghazi has now become a no-go zone for most foreigners following an escalation in militia violence in recent months.
US ambassador Chris Stevens was murdered in the city in September when the American consulate was stormed by militants.
In June, two British bodyguards were injured in an attack on a convoy carrying the British ambassador to Libya.
UK nationals have been urged to avoid the region for some time because of the high threat of criminal and terrorist kidnappings.
The Foreign Office (FCO) has advised against all travel to much of Libya, and all but essential travel to Tripoli and a handful of other towns.
In January, it urged Britons to leave Benghazi after it became aware of a "specific and imminent threat".
The French military action in Mali, which has received British support, has also raised the threat of retaliatory strikes on westerners.
Advice on the FCO website states: "There is a high threat from terrorism including kidnapping.
"This threat is increased due to a threat of retaliatory attacks following the French intervention in Mali."Suggest a correction