Istanbul - The Latest on the referendum in Turkey, set to decide whether more power should be concentrated in the hands of the president (all times local):
Turkey's state-run news agency says two people have died in a fight outside a polling station in the southeast province of Diyarbakir.
Anadolu news agency said a quarrel between two families turned deadly Sunday in a village school's garden where people were casting their votes on Turkey's referendum.
Voters are deciding Sunday whether to approve or reject changes that greatly expand the president's powers.
The agency said the reasons for the fight were unknown. The private Dogan news agency reported it as caused by "differences in political opinion."
One person remains hospitalized, and two others have been detained in the incident.
Kemal Kilicdaroglu, the leader of Turkey's main opposition party and campaigner for a "no" vote in the referendum on constitutional amendments, has cast his ballot in the capital Ankara.
"We are voting for Turkey's fate today," Kilicdaroglu said, adding: "we hope the results will be good and together we can have the opportunity to discuss Turkey's other fundamental problems."
Kilicdaroglu, who leads the Republican People's Party, has been a vocal critic of the proposed constitutional amendments, arguing that increased presidential powers would lead to "one-man rule" in Turkey.
More than 55 million people are registered to vote in Sunday's historic referendum.
Turkey's President Recep Tayyip Erdogan has cast his ballot in Istanbul in a referendum he described as a "not an ordinary vote."
Speaking to reporters after voting, Erdogan said: "We have held referendums before. But this referendum is now about a new administrative system for the Republic of Turkey, it's a choice for change and transformation."
"We need to make a decision that is beyond the ordinary," he said, adding that he hopes the nation will make the "expected" decision.
"I believe in my nation's democratic common sense," he said.
Bodyguards with automatic weapons stood guard outside the polling station as the president and his wife Emine Erdogan cast their ballots. Two of their grandchildren accompanied the couple.
Scores gathered to greet the president and snap pictures outside the polling station.
Turkey's Prime Minister Binali Yildirim has cast his vote in the western province of Izmir, saying the outcome of the referendum is for the nation to decide.
Speaking to reporters outside the polling station after casting his vote, he said: "Whatever the result is, we will hold it in high esteem. The decision of our nation is the most beautiful decision."
The crowd in the polling station chanted, "Turkey is proud of you."
Both Yildirim and President Recep Tayyip Erdogan have led the campaign for a "yes" vote in the months leading up to the referendum.
Voters are deciding on Sunday whether to approve constitutional amendments that would replace the parliamentary system with a presidential one, scrapping the office of the prime minister and handing its powers to the president.
Turkish Foreign Minister Mevlut Cavusoglu has lambasted foreign countries for attempting to influence Turkey's historic referendum as he cast his vote in the southern province of Antalya.
Cavusoglu said some "from abroad" ''tried to tell the Turkish nation what to do. They took sides but today the decision belongs to our nation."
He did not specify who he was referring to, but tensions have been high between Turkey and some European countries, particularly Germany and the Netherlands. President Recep Tayyip Erdogan branded both countries Nazis for not allowing Turkish ministers to campaign for a "yes" vote there.
The Netherlands withdrew Cavusoglu's landing permission in March, barring him from addressing expatriate Turks there. Turkey said it would impose sanctions and halted high-level political discussions.
Polls opened Sunday in a crucial referendum on whether to increase presidential powers.
People were already lined up at an Istanbul polling station before it opened for Turkey's historic referendum on whether to grant sweeping powers to the president's office.
"We are here early to say 'no' for our country, for our children and grandchildren," said retired tax officer Murtaza Ali Turgut. His wife Zeynep agreed, saying: "I was going to come sleep here last night to vote at first light."
Another "no" voter, Husnu Yahsi, said: "I don't want to get on a bus with no brake system. A one-man system is like that."
In another Istanbul neighborhood, a "yes" voter expressed full support of President Recep Tayyip Erdogan. "Yes, yes, yes. Our leader is the gift of God to us. We will always support him. He's governing so well," Mualla Sengul said.
The first polling stations have opened in Turkey's historic referendum on reforms that would concentrate power in the hands of the nation's president.
The 18 constitutional changes would convert Turkey's system of government from parliamentary to presidential, and abolish the office of the prime minister.
President Recep Tayyip Erdogan, who called the referendum and has championed the "yes" campaign, says the proposed "Turkish style" presidential system will ensure the country no longer risks having weak governments. Opponents fear the change will lead to autocratic one-man rule, ensuring Erdogan, who has been accused of repressing rights and freedoms, could govern until 2029 with few checks and balances.
Polls in the east opened at 7 a.m. (0400 GMT), while those in the west are to open an hour later.