A month after local elections which saw it lose control of Turkey’s two largest cities, officials in President Tayyip Erdogan’s AK Party are questioning an alliance with nationalists which some blame for one of its biggest electoral setbacks, reports Reuters.

Under a deal between Erdogan’s Islamist-rooted party and the smaller Nationalist Movement Party (MHP), the nationalists fielded no mayoral candidate in the capital Ankara or Istanbul in the March 31 vote, and the AKP stood aside in other regions.

But the deal failed to prevent the secularist Republican People’s Party (CHP), which had a similar pact with other smaller opposition parties, winning the mayoralty in both cities, ending a quarter century of control by the AKP and its Islamist predecessors.

The AKP is still challenging its narrow loss in Istanbul, Turkey’s largest city and business hub where Erdogan himself served as mayor before the party swept to power nationally in 2002. It has dominated Turkish politics ever since.

While the Istanbul appeal drags on, the rare defeat has prompted questions within the party over campaign strategy. Although the alliance helped them win a majority of votes nationwide, AKP officials say it has delivered limited benefits.

“The MHP gained a lot from this alliance, more than us,” a senior official at the AKP headquarters in Ankara told Reuters.

Another AKP official said the MHP’s 71-year-old leader Devlet Bahceli, once a staunch critic of Erdogan, was an unpredictable ally.

The AKP relies on the MHP for its parliamentary majority, meaning any break in the pact would leave it looking for new partners - a significant challenge after Erdogan’s blistering criticism of his opponents during the campaign.