The two former ruling parties of Senegal ex-presidents Macky Sall and Abdoulaye Wade have formed a coalition for a snap legislative election on Nov. 17 that may pose a big challenge to recently-elected President Bassirou Diomaye Faye.

Sall's Alliance for the Republic party (APR) and Wade's Senegalese Democratic Party (PDS), who announced their unexpected alliance on Sunday, had 106 of 165 seats in the outgoing national assembly.

Since his election, Faye and firebrand prime minister Ousmane Sonko have embarked on financial audits of the former administration, imposed travel bans on some former officials, and appointed mostly their party officials to key positions, leading to a fallout with some former allies.

The move by APR and PDS could disrupt Faye's bid for his Pastef party to secure a majority and hinder his promised reforms. That, in turn, could further destabilise Senegal's political landscape and stir unrest.

Faye, who came to power in April after a landslide election victory, dissolved the house two years into its five-year term on Sept. 12. He said working with the assembly was difficult after the opposition refused to pass bills from the executive.

The APR, and the PDS, which backed Faye in the presidential election against the APR candidate, said in a statement their coalition would be open to allies and other political parties to ensure a big win in the legislative vote.

The APR said in a separate statement that former prime minister Idrissa Seck, who has run for president several times, would also join the coalition.

The Pastef party competed in the 2022 legislative election under the opposition Yewwi Askan Wi coalition that won 56 seats. It will run under its own banner in the upcoming poll.