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.
Washington targets Iran's fortified missile sites near Hormuz
The US Central Command (CENTCOM) has announced late on Tuesday that its forces are carrying out strikes at fortified missile sites on the Iranian coast near the Strait of Hormuz.
Iran confirms death of security chief Larijani
Iran has confirmed the death of senior political figure Ali Larijani, a key member of the country’s security establishment, amid ongoing regional conflict.
Trump says NATO's refusal to help on Iran is 'very foolish'
President Donald Trump on Tuesday said the United States had been informed by most of its NATO allies that they did not want to get involved with the country's military operation in Iran, a move he described as a "very foolish mistake".
US National Counterterrorism Center director resigns over war in Iran
The head of the National Counterterrorism Center Joseph Kent resigned on Tuesday, becoming the first and most senior member of US President Donald Trump's administration to resign over the war in Iran, saying Tehran posed no imminent threat to the United States.
France will never take part in operations to unblock Hormuz Strait, says Macron
President Emmanuel Macron said on Tuesday France would never take part in operations to unblock the Strait of Hormuz, pushing back on comments by U.S. President Donald Trump that Paris was willing to help.
