The United Nations has revealed it has received allegations of sexual abuse and other serious misconduct by its peacekeeping troops in Mali.

The incidents were said to have taken place in the northeastern town of Gao on September 19 and 20, Secretary-General Ban Ki-moon's spokesman was quoted as saying in a statement from the U.N. released on Monday which didn't give details about the accusations.

Leaders from across Africa and France watched the inauguration of Mali President Ibrahim Boubacar Keita in front of thousands of his supporters on Thursday as the nation entered a new era of democracy after months of political chaos.

Idriss Deby of Chad, the Ivory Coast's Alassane Ouattara and Moroccan king Mohammed VI were prominent guests among numerous heads of state invited to welcome the new leader, elected by a landslide on August 11.

Mali's new government on Wednesday set November 24 as the date for the first parliamentary elections since a military coup last year which led to a sweeping Islamist occupation and a French-led military intervention.

The announcement comes two weeks after Mali's first post-war president Ibrahim Boubacar Keita appointed Prime Minister Oumar Tatam Ly to lead the west African nation's return to stability after 18 months of political chaos.

France is enlisting the help of Malians to police its aid projects in the west African country with an innovative crowdsourcing project asking people to report corruption by text or online.

The foreign ministry's project is the first of its kind in France, which has pledged 280 million euros ($374 million) in aid to Mali after it helped the west African country oust al-Qaida-linked groups that were occupying the vast north.

A group of 160 Chadian troops from the United Nations peacekeeping force in Mali have deserted their posts in a dispute over pay and conditions, a military source and the soldiers themselves told Agence France Presse on Tuesday.

A Chadian army captain claiming to be the leader of the deserters told AFP by telephone his men had left their posts in the northeastern town of Tessalit overnight from Monday to Tuesday and were heading to the city of Gao.

Al-Qaida's north African branch has released a video purporting to show seven kidnapped Westerners, the Mauritanian news agency ANI reported, footage France's foreign ministry deemed "credible.”

The hostages are four Frenchmen kidnapped from a uranium compound in northern Niger exactly three years ago along with a Dutchman, a Swede and a South African who were abducted from Timbuktu in northern Mali in November 2011.

At least two Malian soldiers were wounded as the army exchanged fire with "bandits", killing three during security operations near the Mauritanian border, security sources said on Thursday.

Troops had been on patrol around the market town of Lere as part of week-long security operations across the country, when they encountered the gunmen on Wednesday, the army and defense ministry told Agence France Presse.

Mali's first post-war prime minister began forming a government as the United States and France gave an early vote of confidence to the new administration, pledging support.

Career technocrat Oumar Tatam Ly was named as head of President Ibrahim Boubacar Keita's government on Thursday, taking over from interim premier Diango Cissoko.

Ibrahim Boubacar Keita was sworn in on Wednesday as Mali's new president after winning a landslide victory in elections called to turn the page on months of political chaos and conflict.

Keita, a former prime minister, vowed to work for African unity as he began his five-year term in the presence of outgoing transitional leader Dioncounda Traore and more than 1,000 Malian politicians, diplomats and military personnel at a ceremony in the capital Bamako.

At least 23 people have been killed in flash floods caused by torrential rain in the Malian capital Bamako, a government official said on Thursday.

"There have been 23 people killed," Alassane Bocoum, the national director of social development, told Agence France Presse, adding that all had been identified.