Ivorian President Allassane Ouattara has been sworn in for a third term in office.

The solemn ceremony was attended by 13 African counterparts as well as former French president Nicolas Sarkozy.

"Before the sovereign people of Ivory Coast, I solemnly swear on the honour to respect and faithfully defend the Constitution, to embody national unity, to ensure the continuity of the State and defend its territorial integrity". Ouattara said as he took the oath of office.

The 78 year old won a disputed third term at the ballot box on October 31.

The opposition says he breached the constitution by seeking a third term and has mounted a campaign of "civil disobedience" aimed at pushing him out.

Ouattara and his supporters had argued that a 2016 revision of the constitution reset his term counter to zero.

When Ouattara won with more than 94 percent of the vote, the opposition cried foul and announced a "transitional government".

Several opposition leaders were arrested, with legal proceedings over "sedition" launched against them.

Pre- and post-election violence is reported according to an official toll to have claimed at least 85 lives since August.