A soldier escorts an election official carrying a bag full of ballots following a voting procedure for a referendum in the Kurdish-dominated southeastern city of Diyarbakir, Turkey, April 16, 2017. REUTERS/Sertac Kayar

ANKARA (Reuters) - The deputy chairman of Turkey’s main opposition Republican People’s Party (CHP) said illegal acts were being carried out in favor of the government in Sunday’s referendum on expanding the powers of the presidency.

“Many illegal acts are being carried out in favor of the government right now, but ‘No’ will win in the end,” Erdal Aksunger told reporters at his party headquarters, referring to an election board decision to accept unstamped ballots.

A statement on the High Electoral Board’s (YSK) website hours before polls closed said it would count ballots that had not been stamped by its officials as valid unless they could be proved fraudulent, citing a high number of complaints that YSK officials at polling stations had failed to stamp them.

With 80 percent of ballots opened, support for the constitutional changes that could hand President Tayyip Erdogan sweeping new powers stood at 53.9 percent, according to the state-run Anadolu news agency.