The board's decision to accept ballots without official stamps was like "changing the rules midgame", he said.
The Istanbul Bar Association filed a criminal complaint against electoral board head Sadi Guven for "wrongful conduct" and "altering the result of the election".
Turkey's three largest cities - Istanbul, Ankara and Izmir - all voted "No" although "Yes" prevailed in Erdogan's Anatolian heartland.
A member of Turkey's main opposition party says the party plans to go the country's top court to challenge the electoral board's 10-1 decision to uphold the results of the referendum expanding the president's powers.
Opposition parties are filing their objections to the electoral board Tuesday for the decision to count as valid ballots that did not bear an official stamp and other alleged irregularities. "Everyone should respect the outcome, especially the main opposition".
Fears the Yes vote in Turkey's referendum which granted far-reaching new powers to Turkey's President may have been unfairly influenced in his favour have been heightened by criticism from an European Union observer sent as an impartial witness.
Sunday's referendum allows Erdogan, who has ruled Turkey first as prime minister and now as president since 2003, to fulfill his long-held ambition for a presidency with executive powers.
(AP Photo/Petros Karadjias). People walk in central Istanbul's Taksim Square, Tuesday, April 18, 2017.
Binali Yildirim made the call during an address to legislators from his ruling party, as the country's main opposition party prepared to apply to the country's highest electoral board to seek an annulation of Sunday's vote which gave President Recep Tayyip Erdogan's "yes" camp a narrow win.
Thousands have been protesting in major cities since Sunday's referendum, which has set into motion the transformation of Turkey's system of government from a parliamentary to a presidential one.
President Donald Trump congratulated Turkish President Recep Tayyip Erdogan, on his contested referendum that granted him broad new powers.
According to unofficial results, the "Yes" campaign won with 51.41 percent, while the "No" votes stood at 48.59 percent.
"The opposition should not call people to take to the streets and say they do not recognize election results".
Anadolu news agency cited a statement by Istanbul Police that said the suspects were detained early Wednesday for attempting to provoke a response similar to the mass anti-government demonstrations that happened across Turkey in 2013. "From the German government's point of view, Turkey must ... clear up the questions that have been raised".
Erdogan has lashed back at the OSCE worldwide monitors' initial findings, telling them to "know their place", Reuters reports.
The mission of observers from the 47-member Council of Europe, the continent's leading human rights body, had already pronounced the referendum to be an uneven contest.
Asked to comment about Erdogan's rebuke, de Zulueta said: "I don't have an opinion, we are invited by the Turkish authorities to observe".
The White House said they also discussed a U.S. missile strike in Syria and the fight against the Islamic State group.
Foreign Minister Mevlut Cavusoglu said that Erdogan and Trump would meet in person next month, before a North Atlantic Treaty Organisation summit.