A newspaper editor has been released from detention in Mauritania, but dozens of suspected Islamic activists remain in custody awaiting charges in a crackdown by the government on what it says is a budding terrorist organization.

Following his release Saturday, editor Mohamed Mahmoud Ould Ebilmaali, of the independent daily Akhbar Nouakchott, said he was asked to locate a leader of the Islamist opposition, whom he interviewed a few days ago, but he refused.

Police have arrested between 30 and 40 suspected Islamist activists in recent weeks, while up to 40 more remain on a most wanted list.

Mr. Ebilmaali said he was released because he is not an activist. Another journalist, Mohamed Ould Abderrahmane, has been in custody since April 25, on suspicion of running an activist Web site.

Speaking on condition of anonymity, a Mauritanian journalist says he and his colleagues sent a letter to the government late Sunday, asking for Mr. Abderrahmane's immediate release.

He says journalists are also asking to work in a climate free of intimidation.

Mosques are also at the center of the crackdown in Mauritania, a largely Muslim country, which straddles black and Arab Africa. A dozen imams are among those arrested, including the influential Cheick Mohammed Hassan Ould Dedew.

In his last sermon at the Ousama Mosque in Nouakchott, he asked Muslims to act in ideal ways, so as not to infuriate God.

He was detained during the first wave of arrests on April 25. Since then, the government has enforced laws banning meetings and political speeches within mosques.

Communications Minister Ahmoud Ould Abdi said that, during raids inside mosques, documents were seized that allegedly showed plans to carry out attacks.

He said the raids followed the early April arrest of seven men he says were trained in Algeria by the al-Qaida linked Salafist Group for Preaching and Combat. They have since been accused of plotting attacks in Mauritania, as well as trips to Iraq, Afghanistan and Chechnya. The communications minister said interrogations of these suspects led to the discovery of a budding Mauritanian terrorist network.

Those arrested also include former ambassadors, business people and officials from Islamic-funded non-governmental organizations. Under Mauritanian law, charges must be brought within 30 days of their arrest, meaning the first group of the detainees should be charged by Wednesday.

A spokesman for those detained, Saleck Ould Sidi Mahmoud, tells VOA he believes the government is carrying out the crackdown because the Islamists are so popular.

He says it is unfortunate, because, in Mauritania, mosques were one of the last remaining spaces for freedom of expression. He says Islamists in Mauritania are non-violent politicians, who want more democracy and better human rights.

Mauritania's president, Maaouiya Ould Taya, who has been in power since a coup in 1984, has previously carried out waves of arrests within Islamic groups after accusing them of plotting his overthrow. He also maintains close ties with both the United States and Israel, despite opposition from these groups.

The U.S. government has provided anti-terrorism training to Mauritania's army, saying vast areas of the Sahel desert could become training and hiding places for terrorist groups.