The High Electoral Board said it would accept ballots which have not been stamped "valid" by officials. The opposition CHP has slammed the decision.
Turkey's main opposition CHP party has slammed a decision by the electoral board to accept unstamped ballots in Sunday's constitutional referendum.
The High Electoral Board's (YSK) posted a statement on its website hours before polls closed saying it would count ballots that had not been stamped by its officials as valid unless they could be proved fraudulent. The YSK cited a high number of complaints that its officials at polling stations had failed to stamp them.
The deputy chairman of the main opposition People's Republican Party (CHP) said the decision would undermine the legitimacy of the referendum.
"The High Electoral Board has failed by allowing fraud in the referendum," CHP deputy chairman Bulent Tezcan told reporters at the party's headquarters in Ankara.
Around 86 percent of Turks eligible to vote have turned out in Turkey's referendum on transitioning the country to a presidential system, broadcaster Haberturk said on Sunday.