Mali's interim president Dioncounda Traore plans to return home Friday after a two-month stay in Paris where he travelled for treatment after being attacked, diplomats said.

The 70-year-old was attacked by a mob inside his office in Bamako on May 21, the eve of the official start of a transition period for a return to democratic rule in the troubled west African country after a March coup.

"He let it be understood that he wished to return to Bamako tomorrow (Friday)," a diplomat said, adding that Traore planned to "assume his responsibilities" once he got back home.

Renegade soldiers toppled elected president Amadou Toure on March 22 but, under intense regional and international pressure, later agreed to hand power back to a civilian administration.

Traore was attacked by a group of people backing the coup.

Mali has continued its descent into chaos since the coup and is de facto split in two, with Islamist groups linked to Al-Qaeda controlling the north, a territory larger than France or Texas.

Its efforts to escape a post-coup crisis faced further upset on Wednesday after key political parties called for the prime minister to resign, just days before a deadline to form a new unity government.

Interim Prime Minister Cheick Modibo Diarra has until July 31 to formulate a unity government, demanded by regional mediators to deal with the deepening hold of hardline Islamists on the north, which they seized four months ago.