Turkey's ruling party has asked for a recent municipal election it lost in Istanbul to be invalidated.

The Justice and Development Party, or AKP, filed its "extraordinary objection'' to the March 31 election with Turkey's electoral board on Tuesday. Citing alleged irregularities, the party previously pushed for a recount of votes, and the process is still underway in one Istanbul district.

Turkish President Recep Tayyip Erdogan's AKP and its ally won a majority of local election votes across Turkey but lost in the capital of Ankara. In Istanbul, unofficial contested results give the mayoral candidate of the main opposition party, Ekrem Imamoglu, a 13,827-vote lead over AKP's candidate.

The electoral board is expected to rule on the party's request after all recounts are complete. If it accepts AKP's objection, Istanbul could repeat the election on June 2.