Mauritania President Mohamed Ould Abdel Aziz (C) arrives at Indira Gandhi International Airport for the Third India-Africa Forum Summit in New Delhi on October 28, 2015. India is hosting an unprecedented gathering of Africa's leaders as it ramps up the race for resources on the continent, where its rival China already has a major head start. AFP PHOTO / SAJJAD HUSSAIN / AFP / SAJJAD HUSSAIN

Nouakchott - A Mauritanian prisoner sentenced to death for terrorism over an al-Qaeda plot to assassinate the president has escaped from prison, a security source told AFP on Friday.

Cheikh Ould Saleck, on death row since 2011, was last seen by fellow inmates at Nouakchott central prison at midday on Thursday, according to the source.

“His absence from group prayers in the evening alerted his fellow Islamist inmates, who went to get him and found his cell locked,” the source said.

A guard smashed open the door and found a flag of al-Qaeda in the Islamic Maghreb (AQIM), the group's north African franchise, the source added.

Ould Saleck and a fellow AQIM jihadi were arrested on the outskirts of the Mauritanian capital in 2011 when the army foiled their plot to kill President Mohamed Ould Abdel Aziz using two car bombs.

A Mauritanian gendarme was killed and eight wounded in a firefight following the failed attack, while four suspected AQIM members died.

The Nouakchott prison houses more than 30 jihadis, several on death row, although the country's most dangerous inmates are kept in a prison garrison located in the north.