MOUAKCHOTT - Former prime minister Sidi Mohamed Ould Boubacar on Saturday announced he would stand in Mauritania's presidential election as an "independent candidate", but with support from the opposition Islamist party Tewassoul.
Boubacar, 61, said in a statement Saturday he had decided to run as an independent candidates after "deep examination of the situation in the country" and discussions with "political figures and forces".
He was prime minister from 1992-1996 and again in 2005-2007.
He will be running against former general Ould Ghazouani, a close ally of current President Mohamed Ould Abdel Aziz. He quit as defence minister this month after confirming his candidature.
Opposition legislator and anti-slavery activist Biram Ould Dah Abeid has also said he will run.
The presidential election in the conservative Saharan state are scheduled to take place by June 30, at a date that has yet to be set.
President Aziz is stepping down at the end of his second and final term in office.
Despite weeks of talks, the Mauritanian opposition have failed to come up with a unity candidate to take on the ruling Union for the Republic (UPR) party candidate.
Instead, each party is fielding a candidate while "coordinating" positions, especially if a second round-run off vote is required.
Also Saturday, Mauritania declared three days of mourning following the death of former president Lieutenant-Colonel Mahmoud Ould Ahmed Louly, who led the country from June 1979 to January 1980.