Fears for held Sudanese activist

The ICC prosecutor has sought an arrest warrant for Sudan's president

Human rights groups have expressed fears for the safety of a Sudanese activist in detention in Khartoum.

Osman Hummaida was taken into custody along with two other activists and freed after eight hours of questioning.

But they were brought in twice more. After the third session on Wednesday, Mr Hummaida, who also has UK nationality, was not released.

One of the freed activists said they were asked about Darfur and any links to the International Criminal Court.

In July, the ICC's prosecutor requested an arrest warrant for Sudanese President Omar al-Bashir.

They [security forces] interrogated me about the centre's activities and with relation to the Darfur case and the ICC Amir Suleiman Khartoum Human Rights Centre

Sudan's leader was accused of genocide, war crimes and crimes against humanity in relation to the conflict in the Darfur region, which Mr Bashir denies.

An international aid worker - who did not want to be named - told the BBC the authorities wanted to find out who had passed on information to the ICC.

Observers fear more human rights activists could be arrested over the next few days.

Torture concerns

One of the detained activists, Khartoum Human Rights Centre head Amir Suleiman, told the BBC he and a colleague had been arrested along with Mr Hummaida three times since Monday.

"They interrogated me about the centre's activities and with relation to the Darfur case and the ICC," he said.

Unconfirmed reports suggest his colleague Abdel Moneim Al-Jak was badly beaten while he was in custody on Wednesday.

Mr Suleiman said he was due to go for more questioning on Thursday.

"The Sudanese government is well-known for having little tolerance for criticism," said Georgette Gagnon, of the US-based Human Rights Watch.

"This is part of a wider pattern of trying to silence those who support justice and to suppress information about the human rights situation in Sudan," she said in a statement.

Amnesty International said it feared Mr Hummaida was being mistreated in custody.

"Fears for his safety are heightened by the fact that he was previously arrested in 1990 and spent a year and a half in the "ghost houses" of the NSIS [National Security and Intelligence Services], where he was subjected to torture and other forms of ill-treatment," the rights group said in a statement.

According to Amnesty, Mr Hummaida is the former director of Sudanese Organisation against Torture and a United Kingdom citizen.

The UN estimates that up to 2.7 million people have been forced from their homes in Darfur and some 300,000 have died during five and a half years of conflict.

Sudan's government has always denied charges that it armed militias accused of widespread atrocities against civilians in Darfur.

It is lobbying hard for the UN Security Council to delay an ICC investigation into whether President Bashir should be charged.