Soldiers gathered at the presidential palace after Abdallahi replaced senior army officers during a political crisis in the northwest African country, one of the continent's newest oil producers which also mines iron, copper and gold.

A "State Council" led by one of the sacked officers, former presidential guard chief Mohamed Ould Abdelaziz, said Abdallahi was now "former president" and annulled his previous decree sacking Abdelaziz and the heads of the army and Gendarmerie.

The communique, described as the council's "Statement No. 1," was broadcast by Gulf-based al-Arabiya television. State television and radio in Nouakchott had both ceased broadcasting earlier in the day.

Abdallahi won elections last year and took over from a military junta that had ruled since it toppled President Maaouya Ould Sid'Ahmed Taya in a bloodless coup in 2005.

"The security agents of the BASEP (Presidential Security Battalion) came to our home around 9.20 (5:20 a.m. EDT) and took away my father," Amal Mint Cheikh Abdallahi, the president's daughter, told Reuters.

A presidency official who declined to be named said the president, prime minister and interior minister had been arrested and taken to an unknown destination.

Largely desert Mauritania, a former French colony of more than 3 million people, straddles black and Arab Africa.

Abdallahi replaced one government in May following criticism over the government's response to soaring food prices and to attacks over the last year carried out by al Qaeda's north African arm.

But the new government resigned last month in the face of a proposed no-confidence vote.

A new one was formed but without the opposition Union of Forces for Progress (UFP) and Islamist Tawassoul parties which had formed part of the previous government.

This week most of the members of parliament belonging to Abdallahi's PNDD-ADIL party walked out from the party en masse, in a move some political sources said were supported by senior military officials.