Voting started in most of Turkey at 8am (0500 GMT) on Sunday (April 16) in a referendum on changes in the constitution which will give resident Tayyip Erdogan sweeping powers.

The vote in the southeastern Turkish city of Diyarbakir started one hour earlier at 7am (0400 GMT). Erdogan himself is expected to cast his vote in Istanbul later on Sunday.

Some 55 million people will vote at 167,140 polling stations across the nation on whether to replace the country's parliamentary system with an executive presidency.

Polls will close at 5 pm (1400 GMT).

Southeastern Turkey where Van is located has suffered numerous bombings since the Kurdistan Workers Party (PKK) militant group, which has waged a three-decade insurgency for Kurdish autonomy in the region, abandoned a ceasefire in 2015.

Erdogan views the pro-Kurdish People's Democratic Party (HDP) as the political wing of the Kurdistan Workers Party (PKK) militant group, which has waged a three-decade insurgency in the southeast and claimed responsibility for a deadly attack on a police compound in Diyarbakir on Wednesday (April 12).

The PKK is considered a terrorist group by the United States and European Union.