Turkish expatriates living in Germany began voting on Monday in a referendum which proposes changing Turkey's constitution from a parliamentary to a presidential system.
The vote is taking place amid increasingly strained ties between Turkey and Europe, home to an estimated 2.5 million Turkish citizens eligible to vote. About 1.4 million Turkish nationals living in Germany are eligible to vote.
Turkey's President Recep Tayyip Erdogan argues the proposed strengthening of the presidency will avert instability associated with coalition governments, at a time when Turkey is facing terrorist threats. Critics, including some European leaders, say it will concentrate too much power in the president's hands.
Dozens of people lined up outside the Turkish consulate in Berlin to vote on Monday.
Erdal Cakiroglu, voting in Berlin, said he supported Erdogan's proposed changes.
"We are sticking together for Turkey and the future of the Turkish Republic ... we are here to support the stability of our country."
Tarik Demir, a construction worker in Berlin, also supported the measures. "The AK Party [the governing party] has made positive changes in Turkey. They've implemented social benefits, they built many houses and streets," he said.
Demiral Sadet, a retired bank employee, said many of her friends were apprehensive about returning to Turkey until they saw the outcome of the vote.
Melahat Yildiz was against the changes.
"Until the end will I say no, for my country because I love my country, for the future, for my Turkey and for my grandchildren and for all the children in Turkey I will say no."
In Germany, voting will take place from March 27 to April 9. The ballot boxes will be sealed, then flown to Ankara to be counted on the evening of April 16, when people in Turkey vote.
France has just over 318,000 Turks eligible to vote and the Netherlands nearly 245,600. Austria, Belgium, Britain and Switzerland also have sizeable Turkish communities.
In the US, the vote starts on April 1; in the UK on April 6; in the Turkish Republic of Northern Cyprus (TRNC) and The Netherlands on April 5; in Italy and Saudi Arabia on April 7; and in Greece and Russia on April 8.
TRT World's Kilmeny Duchardt spoke with Sule Gurel, Dusseldorf Consulate General of Turkey.
Early voting in Turkey
Turkish expatriates heading abroad also started to vote on Monday at Istanbul's Ataturk International and Sabiha Gokcen airports.
"A new period begins. I hope this will be good for Turkey," said Halil Gemici, a Turkish citizen living in Switzerland.
"It doesn't matter much if the outcome is 'yes' or 'no'. We have one country and that is Turkey," he said.