Mauritanians are voting for the first time since the country gained independence from France in 1960.
The 62-year-old is standing down after serving the maximum two five-year elected terms.
However the status quo is likely to prevail when a new leader is elected.
Abdel Aziz has expressed his support for Mohamed Ould Ghazouani, who is a former general and defense minister.
Germany's Merz arrives in Kyiv to the sound of sirens and explosions
The sound of air raid sirens and explosions rang out in Ukraine's capital Kyiv on Sunday as German Chancellor Friedrich Merz arrived for a visit to show support for President Volodymyr Zelenskyy amid escalating Russian attacks.
Protests demanding Indian election chief resigns escalate
Thousands of youth protesters and opposition supporters rallied in Delhi and Mumbai on Sunday to demand the resignation of India's election commission chief over changes to voter rolls, as police detained some demonstrators for a third day.
US Coast Guard finds debris from missing medical aircraft off Nantucket
The US Coast Guard said late on Saturday it found debris from a medical transport aircraft off the shore of Massachusetts' Nantucket island and was searching for six people who were on board.
Trump names intelligence chief as AI czar
US President Donald Trump has appointed Director of National Intelligence Jay Clayton as the administration's AI czar, the Wall Street Journal reported on Saturday, citing an interview with Clayton.
Trump shares Republican senator's phone number in feud over time switch
US President Donald Trump shared online the supposed phone number of a Republican US senator in the first of multiple posts on Saturday in a row over making daylight saving time permanent.
