ANKARA, Turkey — Looking ahead to elections next year, President Recep Tayyip Erdogan of Turkey has been conducting a vigorous housecleaning, pledging a “serious renewal” of his governing party.

Almost every weekend, the president is in local districts and cities overseeing party elections. In recent months, his micromanagement has even reached into the ranks of municipal governments, forcing the resignations of six mayors from some of Turkey’s most important cities, including the capital, Ankara.

Most of those who were pushed out had failed to deliver a yes vote during the April referendum that approved constitutional changes that would give Mr. Erdogan expanded powers as president if he were to be re-elected.

Indeed, the referendum failed in 17 of Turkey’s 30 largest cities — reflecting growing concerns that the president was acquiring too much clout.