Ansar Dine spokesman Senda Ould Boumama “went to the Mauritanian armed forces on the border”, near the southeastern town of Bassiknou, on Saturday evening, the source said without giving further details.
According to Mauritania’s independent ANI news agency, Ould Boumama was transferred during the weekend to the capital Nouakchott, where he is being interrogated by police.
He first expressed a desire to surrender and be extradited to face trial in Mauritania, his home country, in a telephone call on April 17 to ANI, which is frequently used by Al Qaeda’s north Africa chapter to post messages.
Ould Boumama claimed to have been the target of an assassination attempt, although he did not reveal the origin.
The surrender will be seen as a further blow to Ansar Dine four months after France led a military operation to oust the organisation and other Islamist militias from the towns they had occupied across northern Mali last year.
The militants and Tuareg rebels took northern Mali in the wake of a military coup in the capital Bamako last year that left Mali, formerly once of the region’s most stable countries, in disarray.
Ansar Dine later implemented a brutal interpretation of Islamic sharia law on the people of the north, carrying out amputations and public executions.