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.
One killed, dozens injured in clashes during protest in Pakistan
At least one police officer was killed and dozens of people injured in Pakistan as supporters of jailed former Prime Minister Imran Khan clashed with security forces outside the capital Islamabad on Monday, officials and Khan's party said.
Five killed in plane crash outside Costa Rica capital
A small plane traveling to Costa Rica's capital of San Jose crashed on Monday afternoon, authorities said, killing five of the six passengers on board.
Israel pounds Beirut suburbs as Lebanon says 31 dead nationwide
Israeli strikes pummelled south Beirut on Monday, Lebanese official media said, while health authorities reported 31 people killed across the war-hit country, most of them in the south.
Judge dismisses Trump election subversion case
A US judge on Monday dismissed the federal criminal case accusing Donald Trump of attempting to overturn his 2020 election defeat after prosecutors moved to drop that case and a second case against the president-elect, citing Justice Department policy against prosecuting a sitting president.
Pakistan sectarian fighting restarts, breaking truce
Sectarian fighting in northwestern Pakistan which killed more than 80 people last week restarted on Monday, officials said, breaching a seven-day brokered ceasefire.
