- The "yes" vote appears to have narrowly won in the referendum, with Turkey's electoral board declaring a win for the constitutional changes. Turkey's historic referendum will change the government from a parliamentary democracy to a presidential system, which will see Turkish President Recep Tayyip Erdogan's powers vastly expanded and could see him remain in power until 2029.

- Turkey's main opposition party CHP has said they would challenge the final tally after reporting irregularities at the polls. Episodes of voter intimidation and violence have been reported, with at least three people reportedly being killed in altercations in the southwestern city of Diyarbakir. Election monitors from the opposition, pro-Kurdish HDP party have reportedly been prevented from entering voting stations on a number of occasions.

- The new presidential system will come into force after the general elections in November 2019, centralizing the executive branch under the president, giving Erdogan the direct power to appoint ministers, and dispensing with the role of the prime minister. It will be based on 18 changes to the Turkish constitution.

Read: What you need to know about the Turkish referendum

All updates in Universal Coordinated Time (UTC)

22.10 The European Commission has called on Turkey to seek "the broadest possible national consensus" when implementing its constitutional amendments given the closeness of its referendum.

21.03 According to results from Turkey's state-run Anadolu news agency, the "yes" vote won by 51.2 percent compared to 48.8 percent for the "no" camp with 100 percent of the votes tallied. Official results are to be expected in 11 to 12 days.

20.52 Turkey's main opposition party, the People's Republican Party (CHP), has said they won't accept a "yes" victory. CHP leader Kemal Kilicdaroglu said: "This referendum brought a truth to light - at least 50 per cent of the people said 'no'."

20.34 The head of Turkey's elections board has officially confirmed the passage of the referendum.

20.20 German Social Democrat leader Martin Schulz tweets that the narrow result of the referendum shows that Erdogan does not represent all of Turkey, and that it is imporant to continue to show ongoing commitment to democracy and human rights.

20.09 The leader of the main opposition CHP party Kemal Kilicdaroglu has officially announced that he will be raising objections to actions of the election board during referendum.

20.03 "No" voters have taken to the streets in Istanbul, protesting the result of the referendum and claiming that election fraud had led to the result. Others could be seen banging pots and pans from their windows and calling Erdogan a "thief."

19.49 With 99.3 percent of the votes counted, the distribution of the "yes" vote appears to firmly focus on central Anatolia, while major urban and coastal regions in the west as well as parts of the predominantly Kurdish southeast voted "no."

19.44 President Erdogan announces that among "all the work ahead for us" the issue of the reintroduction of the death penalty will be top, saying that if necessary he will hold another referendum on the issue of capital punishment as well. "If (a parliament bill) comes in front of me, I will approve it. But if there isn't support - then what shall we do? Then we could have another referendum for that," Erdogan said.

19.37 Celebrations have spilled over into Germany. Expat Turks are seen revelling in Berlin's Kufürstendamm shopping mile. DW correspondent Brandon Conradis meanwhile tweets that he saw Turkish flags on cars in Germany's former capital city, Bonn.

19.17 Erdogan celebrates his victory in the referendum, saying "the people have freely spoken their will. We will now work together to make the most important changes in the history of the consitution of our dear country." Erdogan also added his thanks to voters abroad, saying that "we have all witnessed the pains that the our nationals have had to suffer abroad to be allowed to vote," persumably referring to various European governments challenging the legality of Turkish ministers campaigning abroad.

19.15 The Coucil of Europe published the following statement in response to the Turkish referendum: "The Turkish electorate has voted on the amendments to the Constitution. In view of the close result the Turkish leadership should consider the next steps carefully. It is of utmost importance to secure the independence of the judiciary in line with the principle of rule of law enshrined in the European Convention on Human Rights. The Council of Europe, of which Turkey is a full member, stands ready to support the country in this process."

19.12 Turkish President Recep Tayyip Erdogan holds a press conference after the referendum.

19.00 Turkish prime minister Binali Yildirim has officially claimed victory for the AKP and the "yes" camp.

18.42 Turkish prime minister Binali Yildirim speaks to the crowd gathered outside the AKP headquarters, thanking the voters and saying "we vow to make the most of this result to the greatest welfare of our nation. (...) We will always have differing views and differing solutions, but we will always honor and keep our unity. That is the strength of our democracy. (...) Different people defended differing positions during the campaign, but in the end the people cast their "yes" vote and put an end to this discussion. (...) This is the best response that our people could have given to the terror group behind the lowly coup attempt from July 15 (2016) and to foreign groupings trying to break our unity with their animosity. There is no loser in this referendum, but only one winner: Turkey and its noble Turkish people."

18.20 Supporters of the referendum have taken to the streets celebrating what appears to be a win for the "yes" camp. Crowds have gathered outside the headquarters of President Erdogan's AKP party, waving Turkish flags and chanting political phrases. Fireworks were also seen in parts of the country.

18.17 The private Turkish NTV newschannel says that the difference between the "yes" and the "no" vote was 1,281,363 votes.

18.14 The pro-Kurdish opposition HDP has joined calls to challenge the result of the referendum.

18.09 DW correspondent Bernd Riegert says the European Union may have to revisit and reconsider its relationship with Turkey, which is still an EU-candidate country.

18.04 DW correspondent Dorian Jones say that "the outcome is not certain as yet. It is not the resounding victory that Erdogan would have wanted. This may pose problems to Erdogan down the line. Also, the issue of contested ballots over how they were stamped also remains an issue."

DW Head of News Richard Walker meanwhile tweeted that the expat votes could still swing the result.

17.51 Exiled Turkish journalist Can Dündar reports that Turkish writer Levent Gültekin told his "Özgürüz" news portal that "this is the beginning of the end."

17.45 Turkish President Recep Tayyip Erdogan has reportedly called Prime Minister Binali Yildirim to congratulate him on the referendum result, state-run Anadolu news agency reports. Yildirim had campaigned in favor of the changes to the consititution - despite the fact that the referendum result effectively means that he will be losing his job.

17.42 German Foreign Minister Sigmar Gabriel says that people should remain calm regardless of the outcome of the vote, adding that "it's good that the bitter campaign, which also took place in Germany, is now over."

17.39 Turkey's main opposition CHP party has changed it's earlier challenge to the vote from demanding a recount in 60 percent of the votes to 37 percent of the votes cast.

17.37 Turkish President Recep Tayyip Erdogan has called the leader of the nationalist MHP party on the phone to thank him for his support in the endeavour to change the constitution.

17.36 Turkish President Recep Tayyip Erdogan has thanked the people of Turkey for "showing its will at the ballot box" and adding that the "result of the referendum is clear." Opposition voices continue to debate the legitamacy of the vote.

17.34 DW correspondent Diego Cupolo says that pro-government media have been reporting higher numbers of votes counted than those officially opened by the High Electoral Board (YSK), which so far has reported only 64.5 percent of votes counted - as opposed to 98 percent presently reported by the TRT Turkish state broadcaster.

17.29 Turkey's main opposition CHP party has announced that it will demand a recount of up to 60 percent of votes, having said earlier that "illegal acts" were being carried out in favor of the government's position.

Watch video 00:22 Turkish opposition leader denounces 'illegal practices'

17.25 DW correspondent Diego Cupolo says that tensions remain high in Turkey, as "urban votes erase early gains made by "yes" voters in rural areas." The margin between the "yes" and "no" votes has slimmed down to about two percentage points, according to Turkish state media.

17.06 German Justice Minister Heiko Maas sends out a provocative tweet saying, "we would appreciate reading analyses about the referendum in Turkey from Deniz Yücel and other incarcerated journalists as well," referring to a German-Turkish binational reporter who has been held in Turkey for the past two months under terror allegations.

Read: German Turks in Cologne stay cool about Turkish referendum

17.00 Turkish Prime Minister Binali Yildirim will make a public statement on the referendum at 18.00 UTC. With all but three percent of the votes counted, observers expect the "yes" vote to win.

16.41 DW correspondent Diego Cupolo says that final results might take longer than expected to be confirmed, as the race remains close.

16.37 The "no" camp looks set to narrowly prevail in all three of Turkey's biggest cities, Istanbul, Ankara and Izmir - which joinly make up more than a quarter of the countries overall population.

16.28 DW correspondent Dorian Jones reports from Istanbul that the lead of the "yes" campaign is now falling below 52 percent, as votes in western Turkey continue to come in, with majorities there appearing to be against the change. "It looks extremely close. The 'yes' vote continues to fall."

16.22 Deputy prime minister Veysi Kaynak says on TRT that three quarters of the constituencies of the country voted in favor of the changes to the constitution.

16.18 Erdogan advisor Mustafa Akis tells journalists in Ankara: "it looks like the people have approved this new system and I hope it will be very good for our country."

16.13 DW correspondent Simon Young reports from a "no" campaign rally in Berlin that if it comes to a "yes" vote, many fear that Turkey will become a very difficult place. Some people in attendance, he tells, fear that manipulation of the ballots may have taken place. "They're worried that this vote will not ultimately reflect the true will of the Turkish people," Young says.

16.08 The "no" camp has taken the lead in Istanbul, according to Reuters.

16.05 The race tightens towards the end of the count, with the "yes" camp's lead falling to 52.6 percent with 90 percent of the votes counted, according to TRT.

15.48 With 80 percent of the votes counted, the "yes" camp remained in the lead with 53.5 percent, according to TRT.

15.37 According to the private Habertürk newschannel, 86 percent of the Turkish population took part in the referendum.

15.34 The deputy chairman of the main opposition CHP party, Erdal Aksunger, says that "illegal acts" are being carried out to skew the result in favor of the government, according to Reuters.

Read: Observers to guard against voter fraud in Turkey's referendum

15.31 Turkish government broadcaster TRT reports a declining lead for the "yes" vote at 55 percent with two thirds of the ballots counted.

15.22 With 51 percent of vote counted, the "yes" campaign continues to have a lead with 57 percent in the referendum on expanding presidential powers, according to the government-run Anadolu Agency.

15.18 A last-minute decision by Turkey's "High Electoral Board" (YSK) to accept unstamped ballots as valid votes has raised serious concerns about the legitimacy of the vote among opposition voices. CHP deputy chairman Bulent Tezcan said that the "High Electoral Board has failed by allowing fraud" in the referendum.

14.54 With a quarter of the ballots counted, the "yes" campaign appears to lead with about 63 percent, according to the privately owned NTV broadcaster.

14.49 Exiled Turkish journalist Can Dündar reports on his "Özgürüz" news portal that in Suruc, more votes were counted than residents able to vote.

14.46 The non-governmental Turkish Human Rights Association IHD says that a number of election monitors were prevented from entering polling stations in five provinces in the east and south-east of the country.

14.39 Turks living abroad also took part in the referendum, with the majority of expat votes cast in Europe, especially Germany, which has a 4-million stong Turkish diaspora.

14.27 The Turkish government has announced that there was a high turnout at the polls. Some 55.3 million Turkish citizens were eligible to vote domestically in addition 2.9 million abroad.

14.00 Polling stations have closed at 5 pm (1400 GMT) in Turkey's divisive referendum that could vastly expand Turkish President Recep Tayyip Erdogan's powers. Votes will reportedly be counted throughout the evening, as it is predicted to remain a tight race. Voters have cast their ballots with regards to 18 proposed changes to the Turkish constitution which could amount to the biggest political changes in the republic's history since its founding by Mustafa Kemal Atatürk.

Read: Turkey heads to the polls in referendum on expanding Erdogan's powers

Watch video 00:27 Historic referendum underway in Turkey

Opposing voices, opposing views

Voting in Istanbul along with his family, Turkish President Erdogan predicted that "our people will walk into the future." Meanwhile Turkish Prime Minister Binali Yildirim said that "whatever choice comes out on top, our nation will make the most beautiful decision."

Kemal Kilicdaroglu, the leader of the opposition Republican People's Party (CHP) and one of the most outspoken representatives of the "no" camp meanwhile emphasized "we are voting for Turkey's destiny."