Amnesty International has called on the Bahraini authorities to release two teachers who have been in custody since March when they led a peaceful strike protest.
The campaign organisation has reported allegations that one of the teachers had been tortured.
Jalila al-Salman and Mahdi `Issa Mahdi Abu Dheeb were among several board members of the Bahrain Teachers' Association arrested in Manama after the group called for a teachers' strike amid widescale pro-reform protests in March.
Their colleagues have since been released, but the two - the group's former president and vice-president - are still facing trial on charges that include "inciting hatred against the regime" and "calling to overthrow and change the regime by force".
More than 40 security officers raided Jalila al-Salman's house in Manama on 29 March. At first, she was reportedly taken to the Criminal Investigations Directorate and held in solitary confinement and reportedly subjected to beatings for about a week.
She was then transferred to a detention centre in Issa Town, south of the capital, where she remains. Both Jalila al-Salman and Mahdi `Issa Mahdi Abu Dheeb appeared before a military court several times in June before their cases were transferred to a civilian court and postponed until further notice.
After the arrests, the Bahrain Teachers' Association was dissolved by the country's Minister of Human Rights and Social Development and its members replaced by government appointees.
Amnesty International Middle East and North Africa director Malcolm Smart said: "If these teachers are being held solely because they led a peaceful demonstration, they must be released immediately."