Recep Tayyip Erdogan on Sunday declared victory in Turkey's presidential election after unofficial results showed that he had won 52.6 percent of the vote.
The opposition raised doubts about the accuracy and reliability of the figures released by state-run Anadolu news agency, the sole distributor of the official vote tally.
Muharrem Ince and his Republican People's Party (CHP), the main Turkish opposition in the election, said that around half the ballot boxes had yet to be counted, calling on party monitors to remain with the ballot boxes and keep watching.
Polls closed at 5 p.m. local time, and though Turkey does not have exit polls, the Supreme Electoral Council said it hoped to announce preliminary results before midnight. "In this election we have given them a strong message and a good old Ottoman slap".
On the call Putin and Erdogan confirmed their interest in "deepening partnership ties between the two countries", the Kremlin said, singling out priority projects such as the TurkStream gas pipeline and Turkey's first nuclear power plant being built by Moscow. A crackdown launched after the coup has seen 160,000 people detained, and the state of emergency allows Erdogan to bypass parliament with decrees.
Other presidential candidates include Selahattin Demirtas, leader of the pro-Kurdish Peoples Democratic Party (HDP), who is now in jail on terrorism-related charges that he denies.More news: Angry Priest Hits Baby For Crying During Baptism
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Investors would welcome the prospect of a stable working relationship between the president and the new Parliament, although they also have concerns about Erdogan's recent comments suggesting he wants to take greater control of monetary policy.
In his victory speech to supporters early on Monday morning, Mr Erdogan vowed to bring the new presidential system into being "rapidly".
Addressing thousands of supporters in Ankara, he said: "We will fight even more with the strength you provided us with this election".
Under the new system, the office of prime minister is abolished, parliament's powers curtailed and the president is accorded wide-ranging executive authority.
The CHP said it had recorded violations in particular in the southeastern province of Sanliurfa. It remains to be seen whether Erdoğan will take this as an opportunity to address the long list of challenges facing Turkey and reconstruct its democracy and economy, and regain the respect that he once enjoyed internationally.
Parliament has been weakened and the post of prime minister abolished, as measures approved in a controversial referendum a year ago take effect. That, coupled with high inflation rates and fears that the central bank's independence will be further reduced, has left worldwide investors uneasy after Erdogan's victory. Erdogan says his tough measures are needed to safeguard national security.
The CHP's presidential candidate Ince also accused election reports from the Anadolu Agency of "manipulation".
Luxembourg's foreign minister, Jean Asselborn, noted on Monday it is now up to Erdogan to decide whether Turkey's relations with the European Union will improve.
The restrictive legal framework and powers granted under the ongoing state of emergency restricted the freedoms of assembly and expression, including in the media, said the observers.