Police in Zanzibar have confirmed they are questioning two men over an acid attack on two charity workers.
Five men had originally been held for the attack on the teenagers from the UK in which they had acid thrown over their faces, chests and hands while they were walking through Zanzibar city.
Religious leaders on the island said they believe a radical Islamic group may have inspired the assault.
Kirstie Trup and Katie Gee, both aged 18, were flown to Tanzania’s commercial capital Dar es Salaam for treatment before returning to their homes in London.
Their injuries are not thought to be serious. Doctors who treated them said it appeared the acid had been diluted.
The two young women has been working as volunteer teachers at a Roman Catholic nursery school in a programme run by a charity called Art in Tanzania.
Police described the attack on them as “an isolated incident”, refusing to link it to rising religious tension on the island between majority Muslims and its Christian population.
A separatist group in Zanzibar is pressing for the Indian Ocean island to end its 1964 union with mainland Tanzania, which is ruled as a secular country.
They want to introduce Muslim Sharia law and have clashed with police in the past.
In November last year a Zanzibar Muslim leader, Sheikh Fadhil Suleiman Soraga, had to be treated in hospital after acid was thrown over him and two Christian leaders were killed early this year in separate attacks.