The decision follows an appeal by President Recep Tayyip Erdogan ‘s ruling Justice and Development Party (AKP) of Sunday’s polls across in both cities.
According to unofficial results in İstanbul, main opposition Republican People’s Party (CHP) candidate Ekrem İmamoğlu appears to have won the city’s mayoral seat, beating the ruling AKP candidate Binali Yıldırım by some 27,000 votes.
In capital Ankara, CHP's mayoral candidate Mansur Yavaş scored a victory against his AKP rival Mehmet Özhaseki.
Turkey's Supreme Election Council (YSK) earlier on Wednesday had announced that it would recount local election votes in eight districts of Istanbul, reversing the earlier decision of the provincial electoral board.
YSK Chair Sadi Güven said that vote recount may take place without waiting on the result of and appeal by the main opposition CHP, pro-government Islamist Yeni Akit said.
Accordingly, invalid votes in a total of 16 districts and all votes in three districts of İstanbul will be recounted, Sabah said.
Invalid votes in the districts of Küçükçekmece, Beyoğlu, Başakşehir, Maltepe, Büyükçekmece, Çekmeköy, Eyüp, Fatih, Silivri, Tuzla, Sarıyer, Ataşehir, Beykoz, Şile, Bayrampaşa and Ümraniye will be recounted while all votes in the districts of Çatalca, Silivri and the first district of Kartal.
In capital Ankara, recounts will take place for the districts of Polatlı, Çubuk, Pursaklar, Altındağ, Gölbaşı, Şereflikoçhisar, Keçiören, Sincan, Bala and Çankaya.
"The recount must be completed as soon as possible," YSK’s Güven stressed on Wednesday.
Meanwhile, CHP İstanbul deputy Gürsel Tekin claimed that ballot box committee members were being investigated by the an ID checking technology called GBT, left-wing Gazete Duvar reported.
"What point is there in investigating people at this time? What are you trying to do?" Tekin said, referring to the Turkish government. "These elections are over and the YSK has announced the results.’’