ISTANBUL - Challenges are growing to the validity of Sunday's referendum in Turkey to extend the country's presidential powers.
"Referendum won by cheating," declared Osman Baydemir, spokesman of the pro-Kurdish HDP, Turkey's second-largest opposition party.
An HDP report on the vote said 2,462 "No" campaigners were detained and 453 jailed during the 85-day campaign. HDP's honorary president and deputy, Ertugrul Kurkcu, said the past two months were a "total violation of democratic principles."
Kurkcu said the investigation revealed widespread abuse on voting day.
"It's obvious," he said. "Fraud is extensive. Invalid ballots and envelopes were very widely deliberately used, as well as people forced to vote openly in remote districts and villages, using votes for people who are away from their homes, like construction workers or agricultural migrant laborers."
Under Turkey's election law, all ballots and the envelopes they are placed in have to have an official stamp — a measure aimed at preventing vote stuffing. But on voting day, the Supreme Election Board sanctioned uncertified ballots.
The Organization for Security and Co-operation in Europe (OSCE), which monitored the election, strongly condemned the move in an interim report Monday. The report also highlighted difficulties of monitoring voting procedures in the predominantly Kurdish southeast, citing cases of its monitors being temporarily detained by security forces.
The HDP, too, claimed its monitors were excluded by security forces from numerous voting stations in rural parts of the southeast, the center of renewed fighting between Turkish security forces and the Kurdish PKK.
"There is much greater presence of security forces in the region than there has been for many years," observed Emma Sinclair-Webb, a Turkey researcher with Human Right's Watch. "We've seen pictures circulating on social media of people armed in front of ballot boxes, taking photos of those voting at ballot boxes. Of course, this could have had an intimidating effect on people voting, and this needs investigating."
On Tuesday, the Supreme Election Board dismissed all complaints and calls by opposition parties for a revote. The decision was made in less than a day, despite calls by the European Commission for a full and transparent investigation. The ruling cannot be legally challenged and Prime Minister Binali Yildirim declared the issue resolved.
The referendum to turn Turkey from a parliamentary to an executive presidency was carried out under Emergency Rule and only narrowly passed by 51 to 49 percent of the vote.
President Recep Tayyip Erdogan, who led the "Yes" campaign, saw his traditional strongholds of Turkey's largest cities vote against him, including Istanbul and Ankara. The Kurdish region voted 40 percent yes, significantly higher than the support Erdogan's AK Parry secured in November's general election.
Throughout his campaign, Erdogan courted the Turkish nationalist votes, taking a hardline against the pro-Kurdish right movements. He has presided over an unprecedented crackdown on the PKK since a collapse in the peace process in 2015.
The referendum vote is being interpreted by the presidency as a turning point.
"By making a very clear distinction between the Kurds and the PKK, President Erdogan and the government have won the Kurdish confidence again" wrote Presidential adviser Ibrahim Kalin in Sabah newspaper.
The HDP acknowledged that all the voters the "Yes" camp cannot be explained by fraud.
"Under the circumstance, imagine a town already destroyed by military, the leadership of popular movement is crushed the people left alone," said Kurkcu. "Face to face with the aggressors, under those circumstance, people have to make their decision before the barrel of a gun. But Erdogan won with fraud, and this referendum is stained by fraud."
The president and his government dismiss such concerns as belonging in the past, arguing it is time to look to the future.