ANKARA - Turkey's main opposition party said Friday it would challenge at a top court a last-minute change to voting rules in last weekend's referendum on expanding President Recep Tayyip Erdogan's powers.
The 'Yes' side won 51.4 percent of the vote in Sunday's referendum on creating an executive presidency, axing the role of prime minister from 2019.
But there was anger and shock after the Supreme Election Board (YSK) made a last-minute decision to accept ballot documents in envelopes without an official stamp, which the opposition argues opened the way for fraud.
"We are opening a case at the Council of State calling for the cancellation of YSK's decision to allow unsealed ballots," the Republican People's Party (CHP) deputy leader Bulent Tezcan said in a statement, quoted by CNN Turk broadcaster.
The Council of State, set up during the Ottoman empire, is the country's highest administrative court.
Together with the third largest pro-Kurdish Peoples' Democratic Party (HDP), the CHP called for the referendum to be annulled this week.
On Wednesday, 10 members of the YSK decided against annulling the vote, while only one voted in favour.
In the statement, Tezcan urged the results not to be finalised until the case was concluded and said the party's lawyer would deliver the paperwork to the court later on Friday afternoon.
"Whether citizens said 'Yes' or 'No', we will continue our legal fight until the end to protect the rights of the 49 million citizens who voted," Tezcan said.
Turkish Prime Minister Binali Yildirim responded by saying it was "not the democratic way to go to court, to make complaints to fix the people's decision".
Speaking to reporters in Ankara, Yildirim said the CHP and others had the right to challenge but "there was nothing we could say about using this".
Yildirim added: "The people have made their decision.... Disagreeing with the people's decision suggests not believing in democracy as much as necessary."
He described such efforts as "futile" and said there was "no point in wasting more of everyone's time".