Two members of a Zimbabwean gay rights association are in custody, their lawyers say. They say the two are facing charges of possessing pornographic material and insulting President Robert Mugabe. Ellen Chadian - administrator of the group, Gays and Lesbians of Zimbabwe - and Ignatius Muhambi - an accountant - were picked up during a raid. Homosexual acts are illegal in Zimbabwe, but the group has been allowed to operate openly. Dzimbabwe Chimbga, a lawyer representing the pair, said they had been arrested on Friday. "The initial charges are that they were found in possession of pornographic material," Mr Chimbga said. "Now the police want to add a charge of insulting the president," he added. Police told by AP news agency say that they had found a letter undermining President Mugabe during the raid. Mr Mugabe has in the past described same-sex partners as "lower than dogs and pigs", but arrests of gays are rare in Zimbabwe, correspondents say. Homosexual acts are illegal in most African countries. Last week a judge in Malawi sentenced a gay couple to 14 years in prison with hard labour after they held a traditional engagement ceremony.