Two young British women have been attacked with acid on the east African island of Zanzibar, reports say.
The women had the corrosive substance thrown in their faces during the late-night assault, Sky News said.
A spokeswoman for the Foreign Office said: "We are aware of an incident and are providing consular assistance."
She added that officials became aware of the incident on Wednesday night.
Deputy police commissioner Mkadam Khamis told Sky News: "Police in Zanzibar have launched a manhunt, and we ask for public assistance in identifying the attackers."
Zanzibar is an archipelago of islands in the Indian Ocean around 22 miles off the coast of mainland Tanzania.i
Both women are reported to be aged 18 and are understood to have been attacked in the Stone Town area of Zanzibar's eponymous capital, on the west coast of the island.
The Foreign Office travel advice for Tanzania warns that although most visits to the country are trouble-free, "violent and armed crime is increasing".
The advice, available on its website, says: "Mugging, bag snatching (especially from passing cars) and robbery have increased throughout the country."
It adds: "In Zanzibar incidents have taken place in Stone Town and on popular tourist beaches."