Lawyers for Mauritania's leading opposition politician say he has not had legal advice, access to his doctors or been allowed visits from family members since he was arrested after losing the November 7 election.

A spokesman for lawyers representing Mohamed Khouna Ould Haidallah told a news conference in Nouakchott, Mauritania's capital, they have not been able to see him since his arrest.

The spokesman, Me Brahim Ould Ebetty, called for senior officials to intervene to enable the lawyers to see their client, and to ensure that his case is handled according to the law.

Mr. Ould Haidallah was arrested a few days before the election, and then released in time for the voting. He and several colleagues were arrested again the following day. His security chief was arrested on Tuesday.

The government has said they were plotting a coup d'etat, and hoarding weapons to support the plan. Mr. Ould Haidallah and his supporters have denied the charges.

Mr. Ould Haidallah is a former president who came to power in a coup in the early 1980s. He was overthrown in another coup by the current president Maaouiya Ould Taya.

President Ould Taya was re-elected in the November 7 election. But the opposition and human rights groups say there was massive cheating.

Mr. Ould Haidallah's political adviser, Mohammed Ould Rashi, says the politician remained under arrest.

Mr. Rashi confirmed that Mr. Haidallah has had no access to lawyers or medical services, and he has not been able to see his family while in prison.

Mauritania is an impoverished desert state. But recent oil finds off the coast promise tens-of-millions of dollars in government revenue in the coming years.