Turkish citizens have begun voting in a key referendum on whether to adopt a presidential system with extended executive powers.

The constitutional changes proposed in Sunday's vote seek to transform Turkey's governance from a parliamentary system to an executive presidency, significantly expanding the powers of the top office.

People started casting their ballots in eastern Turkey at 7am (04:00 GMT), while voting in the rest of the country started at 8am (05:00 GMT). Polls will close at 4pm (13:00 GMT) in the east and 5pm (14:00 GMT) elsewhere.

Turkish President Recep Tayyip 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.

The changes are backed by Erdogan, the ruling Justice and Development Party (AK Party) founded by him, and the leadership of the far-right 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 that the amendments will give too much power to one individual, undermining the separation of powers in the government.

"We are going to vote for Turkey's future. Would you let your children go on a train without any brakes?" Kemal Kilicdaroglu, the leader of the CHP, said at a rally in Ankara for the "No" campaign.

A "Yes" vote in the referendum will give 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 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 the ISIS have killed hundreds of security forces and civilians.

Turkey's relations with the European Union (EU), 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.

PHOTO CAPTION

A billboard carrying a picture of Turkish President Tayyip Erdogan and a slogan that reads: ''Yes. It is for the people to speak and to decide'' is seen on a building ahead of the constitutional referendum in Istanbul, Turkey April 13, 2017. REUTERS

Al-Jazeera