International election observers from the OSCE (Organization for Security and Co-operation in Europe) reported on Monday that Turkey's constitutional referendum was contested on "an unlevel playing field."

Despite the technical aspects of the voting process being well administered, voters weren't provided with impartial information on key aspects of what they were voting for, the joint mission of the OSCE's Office for Democratic Institutions and Human Rights (ODIHR) and the Parliamentary Assembly of the Council of Europe (PACE) said in a statement.

"The referendum took place in a political environment in which fundamental freedoms essential to a genuinely democratic process were curtailed under the state of emergency, and the two sides did not have equal opportunities to make their case to the voters," Tana de Zulueta, head of the ODIHR limited election observation mission, said.

Media coverage was dominated by the "yes" campaign, de Zulueta said, a factor which, along with the arrests of journalists and the closure of media outlets, "reduced voters' access to a plurality of views."

De Zulueta also said the campaign was imbalanced due to the involvement of leading local and national officials on the "yes" side.

"We observed the misuse of state resources, as well as the obstruction of 'no' campaign events. The campaign rhetoric was tarnished by some senior officials equating 'no' supporters with terrorist sympathizers," de Zulueta added.

'Important safeguard removed'

The observers also expressed concerns about a decision by the electoral commission to count ballots which did not carry an official stamp.

"Late changes in counting procedures removed an important safeguard," said Cezar Florin Preda, head of the PACE delegation said.

"In general, the referendum did not live up to Council of Europe standards. The legal framework was inadequate for the holding of a genuinely democratic process," Preda said. The Council of Europe is a 47-member body, of which Turkey is a member, which promotes human rights and the rule of law and is separate from the European Union.

A preliminary vote count showed Turkey voting 51.4 percent in favor of changing the country's constitution to give the president vastly expanded powers. The "yes" vote was boosted by support from Turkish voters living abroad, especially in Germany, Austria, Belgium and the Netherlands.

'Politically motivated' reports

Turkey has been under a state of emergency since a failed coup last July, Erdogan advocated extending it after the results of the referendum were published. The main opposition CHP, meanwhile, has called for a recount.

Responding to the OSCE's assessment, Turkish President Recep Tayyip Erdogan told observers they would achieve nothing by casting doubt over the referendum result.

"Know your place first," Erdogan told the monitors in an address to supporters outside his vast presidential palace in Ankara.

"We neither see, hear, nor know those politically motivated reports that you will draft," he said. "We will continue down our road. This country held the most democratic elections that have never been seen in any other country in the West."