President: Mohamed Ould Abdelaziz
Mohamed Ould Abdelaziz took power in a coup in 2008, and was elected president the following year.
He gained another five-year term in June 2014 with almost 82% of the vote in an election boycotted by most of the opposition.
Mr Abdelaziz, an ally of Western powers in the fight against al Qaeda-linked Islamists in West Africa, faced no major challenger to his rule in the 2014 poll. A delegation of French parliamentarians who observed voting reportedly said the elections could be considered "honest and regular".
Most opposition parties also boycotted the 2013 parliamentary elections, saying the organisers were biased and the process flawed.
Following his 2014 win he promised to work for national unity and pledged "to be the president of all Mauritanians and to guarantee the rights of all citizens".
He said he would use his new mandate to "pursue a policy of strengthening national unity, the independence of the judiciary, the fight against waste and social inequality as well as the reduction of poverty through a better redistribution of the nation's wealth".
President Abdelaziz was treated in France in October-November 2012 after he was shot in the arm in what officials say was a mistaken military attack on his convoy.
Mauritania has had a dozen coups or attempted coups since independence from France in 1960.