Mauritanian authorities have said they are hunting for an Islamist militant who escaped from prison where he was awaiting execution for his part in a plot to assassinate President Mohamed Ould Abdel Aziz.

A statement released on public television late on Saturday urged residents to provide information on the militant, whom they named. It did not say when or how he escaped.

He was arrested in 2011 over alleged links to three vehicles containing explosives heading for Mauritania's coastal capital, Nouakchott.

One of the vehicles was said to have been targeting Abdel Aziz, who had ordered military strikes in Mali against jihadist bases in 2010 and 2011.

Al Qaeda in the Islamic Maghreb claimed responsibility for the plot in a statement released on jihadist forums, according to the SITE Intelligence Group.

Islamist groups hijacked a Tuareg rebellion in early 2012 to seize Mali's desert north. A French-led intervention scattered them a year later, but Islamist fighters stepped up attacks in 2015.

Jihadists believed to have links with each other and other groups beyond West Africa have claimed various acts of violence in the region, including a November attack on a luxury hotel that killed about 20 people.

Abdel Aziz, who was elected in 2009 after seizing power in a coup that ended the tenure of the country's first democratically elected president, was hospitalized in 2012. He said soldiers had accidentally shot him.