Seized Zimbabwe activist in court
Prominent Zimbabwean human rights activist Jestina Mukoko, who went missing for three weeks, has appeared in court in the capital, Harare.
The state-run Herald newspaper says Ms Mukoko is charged with attempting to recruit people for military training to try to overthrow the government.
It is unclear when or where the director of the Zimbabwe Peace Project has been over the past three weeks.
The police denied opposition claims that they had been holding her.
After the brief court appearance on Wednesday, officials said the case was being referred up to the High Court and that Ms Mukoko and several others would be remanded in custody.
The Herald reported a police statement claiming that one of the defendants had tried to recruit a police constable to undergo military training in Botswana.
They are trying to come up with confessions from these activists
Zimbabwean human rights activist
The training would have been used to forcibly depose President Robert Mugabe's government and replace it with one led by opposition leader Morgan Tsvangirai, said the statement.
Ms Mukoko is one of more than 40 human rights activists and opposition supporters who Mr Tsvangirai's Movement for Democratic Change (MDC) say have been abducted in the past two months.
A Johannesburg-based Zimbabwean human rights lawyer, Annah Moyo, said the charges against Ms Mukoko and others could be used by the Mugabe regime as an excuse to declare a state of emergency and withdraw from power-sharing talks.
"They are trying to come up with confessions from these activists... that they have been part of the people who have been trying to overthrow the Zimbabwean government," she said.
"This is an indication of a government that is desperate to do whatever it can find to try and hold on to power."
On Wednesday morning, lawyers in Zimbabwe said they had confirmation that Ms Mukoko was being held at a police station in Harare.
Zimbabwe's Lawyers for Human Rights marched in protest at the abductions
They also said they had managed to locate 14 activists at police stations, but that others were still missing.
Ms Mukoko's whereabouts had remained a mystery since she was allegedly abducted from her home outside Harare on 3 December by 15 armed men.
In an unusual move, a High Court judge had ordered police to search for her and told the national Zimbabwe Broadcasting Corporation to run radio and television appeals for information.
At a press conference on Wednesday, Irene Petras of Zimbabwe Lawyers for Human Rights said Ms Mukoko and others arrested had "fundamental rights and freedoms which are being violated with complete impunity".
Ms Petras claimed the detainees had been held at unknown locations and possibly subjected to torture and degrading treatment.
Members of the lawyers group took to the streets of Harare last week to highlight Ms Mukoko's plight, carrying banners protesting against other alleged abductions.
Ms Mukoko's court appearance comes as international pressure on Mr Mugabe is mounting.
The leader of the governing ANC party in neighbouring South Africa, Jacob Zuma, has described the situation in Zimbabwe as "utterly untenable".
Meanwhile Archbishop Desmond Tutu had said he is "very deeply disappointed" that South Africa has failed to stand up to Mr Mugabe.
But the BBC's Rachel Harvey reports from neighbouring South Africa that there is no sign for now of an attempt to turn rhetoric into action.