Russian President Vladimir Putin on Tuesday congratulated his Turkish counterpart Recep Tayyip Erdogan after Turkish citizens approved constitutional changes in a referendum on Sunday, Turkish state media said.
In contrast with European leaders, US President Donald Trump has congratulated the Turkish president, hours after the US state department mentioned concerns by global observers and urged Turkey to respect the rights of its citizens - chiming with sentiment in European capitals.
Turkey's "yes" campaign was led by the governing AK Party and supported by the right-wing MHP.
"We are here today for the sake of Turkey, to live together, to take a stand for our votes", protester Tezcan Karakus Candan said. The main opposition Republican People's Party (CHP) has said it will challenge the results in court if need be, though political analysts see a change in the outcome as unlikely. In particular, observers pointed to a controversial last-minute decision by Turkey's electoral board to accept ballots that did not have official stamps, saying the move undermined safeguards against voter fraud.
"There is only one thing to do. and that's to annul the referendum", he added.
"Objection to election results should remain there", he said. "This small margin is unfortunate for Turkey, as such a drastic change is preferred to have a broader agreement in society", said Sinan Ulgen, chairman of think tank EDAM.
The YSK said on its website on Sunday, as votes were still being cast, that it had received "considerable complaints" that voters had been given slips and envelopes without official stamps and that it would accept unstamped documents as long as they were not proven to be fraudulent.
The EU's call comes after the Organization for Security and Co-operation in Europe (OSCE) and the Council of Europe, a democracy watchdog, both said in a report that it saw fundamental flaws and an uneven playing field in Turkey's referendum.
Erdogan has dismissed the criticism from the observer mission, telling the monitors that they should "know your place".
In turn, the European Commission has called on Turkey to launch a transparent investigation into the election irregularities.
"Such a speculative statement from a spokesperson can not be accepted", Turkey's EU Affairs Minister Omer Celik told reporters at a televised press conference, calling on the EU to "respect democratic processes".
In another apparent contrast to Trump's congratulations of Erdogan, White House Press Secretary Sean Spicer said on Monday that the official administration position would reflect the outcome of an ongoing assessment by an worldwide commission into the validity of the referendum, not expected until next week.
(Graphic showing results so far: http://tmsnrt.rs/2oNBvKv) Sunday's vote ended all debate on forging a stronger presidency, said Erdogan, who argues that concentration of power is needed to prevent instability.
But the "Yes" vote has even wider implications for Turkey, which joined North Atlantic Treaty Organisation in 1952 and in the last half century has been engaged in a stalled bid to join the European Union.
But in his post-referendum euphoria Erdogan - who can now rule until at least 2029 and likely beyond - indicated he'd like to follow up with referenda on the European Union bid and on reinstating the death penalty.
The EU's executive arm warned Ankara that restoring the death penalty would be a "red line".
"There will be no call to Erdogan from the Commission, certainly not a congratulatory call", a Western official with knowledge of European Union policy told Reuters.
Donald Trump will host Turkish president Recep Tayyip Erdoğan on May 16-17 at the White House, in the first meeting between the two leaders.
In a blow to the president's prestige, the "No" campaign notched up the most votes in Turkey's three biggest cities: Istanbul, Ankara, and Izmir.
What have European leaders said?