Supporters of constitutional changes that seek to extend the powers of Turkey's presidential office have taken lead in a referendum that could change how Turkey is governed.
As of 18:00GMT on Sunday, the "Yes" campaign, which is backed by President Recep Tayyip Erdogan, was leading with 51.3 percent to 48.7 percent with 98.4 percent of votes counted.
The constitutional changes seek to transform Turkey's governance from a parliamentary system to an executive presidency, significantly expanding the powers of the top office.
A victory for the "Yes" vote gives the president new powers to assign ministers, high-level state officials, and vice-presidents, as well as half the members in the country's highest judicial body. It will also allow the president to dissolve parliament, and issue executive decrees and state of emergencies.
The changes are backed by the governing Justice and Development Party (AK Party), founded by Erdogan, and the leadership of the Nationalist Action Party (MHP), whose parliamentary support was vital to take the amendments to a public vote.
The main opposition Republican People's Party (CHP), the pro-Kurdish People's Democracy Party (HDP) and other critics argue the amendments give too much power to one individual, undermining the separation of powers in the government.
After casting her vote on Sunday morning, Macide Dogan, a 67-year-old housewife, told Al Jazeera that Erdogan is a "one-in-a-million" leader and praised Turkey's development under his rule.
"I cast my 'Yes' vote as conservative Muslim against infidels who are threatening Turkey. Erdogan defies the world powers trying to challenge him," she said at a polling station on the Asian side of Istanbul.
"We remember the times [before Erdogan] when young girls with headscarves could not enter universities in this country. We remember the times when there was no proper healthcare and transportation."
Ahmet Erturk, 52, was also a "Yes" voter.
"We were stuck with coalition goverments before [AK Party] came to power. God willing, we will wake up to a more stable Turkey as of tomorrow," he said.
Sezer Sarikaya, a 28-year-old logistics manager, told Al Jazeera he was voting "No".
"I will vote against the constitutional changes as I believe our parliamentary system set up by Mustafa Kemal Ataturk [the founder of modern Turkey] is good for us," he said.
Ayse Mucek, also a "No" voter, said that she feels democracy and rule of law are under threat in Turkey under the current administration.
"Today, there are widespread and arbitrary detentions in Turkey and there is no press freedom and rule of law anymore. This should stop in this referendum. I believe in it," the 65-year-old pensioner told Al Jazeera.
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"I am at an old age. I don't think about my future anymore. But if a 'Yes' vote comes out of this referendum, young people should leave this country for better places."
Erdogan addressed supporters in Istanbul for the last time on Saturday, calling on citizens to vote "Yes" to the constitutional changes.
"[The new system] will strengthen the stable and secure environment our country needs to develop," he said.
In contrast, Kemal Kilicdaroglu, the leader of the CHP, urged supporters in Ankara to back the "No" campaign.
"We are going to vote for Turkey's future," he said. "Would you let your children go on a train without any brakes?"
The Turkish presidency has traditionally been a largely neutral and ceremonial role, without many political responsibilities, as specified under the current constitution.
However, Erdogan has effectively transformed the office into a more politically active one after he became Turkey's first president to be elected by popular vote in 2014 - in line with a set of prior constitutional changes passed in a similar referendum in 2010.
Turkey has been under a state of emergency since a group in the Turkish army tried to overthrow the government in a failed coup attempt in July 2016 that killed around 300 people in total.
In recent years, bomb attacks claimed by, or blamed on, Kurdish fighters' groups and Islamic State of Iraq and the Levant (ISIL, also known as ISIS) have killed hundreds of security forces and civilians.
Turkey's relations with the European Union, particularly with Germany and the Netherlands, have been tense since last month after these two EU member states barred Turkish ministers from holding referendum campaign rallies within their borders, where millions of Turkish voters live.