Hundreds of people have been arrested in Istanbul, with 50,000 police officers located in the city as authorities are trying to break up protests in May.
Public transport was closed to stop the people who reach Taksim Square, where demonstrations have been banned since 2013.
Shots from the Turkish capital have shown clashes between riots and protesters with demonstrators who chant when police move those detainees on buses.
The city saw huge protests in March after the arrest of opposition mayor Ekrem Imamoglu, Turkish President Erdogan's main rival.
On May 1 every year the marches led by workers and alliances are held as part of the international Labor Day festivities in many countries.
Taksim Square – the heart of Istanbul – was under a tight lock, with police and metal barriers on all roads leading to the area.
Authorities were determined, perhaps this year more than ever, to ensure that there were no big protests on the square and they had enough police for riots to guarantee this.
The square, usually busy with lively crowds, looked lifeless, with restaurants and shops closed.
The only time along the police lines was permission. Several labor unions were allowed briefly on Taksim, carrying red flags and flowers.
Standing before the Republican Monument, which noted the founding of modern Turkey in 1923, a speaker complained about the restrictions it faced. Water canon trucks parked a short distance.
On the roads leading to the square, groups of tourists were walking from time to time, dragging suitcases, uncertain where they could go and not be able to get to taxis.
The square was sealed for a few days before May 1, according to AFP news agency.
A student named Murat said the streets were “blocked … as if it were an emergency,” he told AFP.
“We were not allowed in the squares … We were taken from the streets in small groups under torture. This is not a situation we are faced with for the first time. It probably won't be the last.”
On Wednesday, 100 people were detained for planning to protest on the square.
City authorities said on Thursday that 382 people had been arrested for “non -authenticated demonstrations”.
Group Rights Amnesty International has called on Turkey to cancel the ban on demonstrations in Taksim.
Restrictions “are based on all -false security and public order grounds,” said Dinushika Dissanayake, a specialist at Amnesty in Europe.
In a statement, the group urged employees to observe the right to protest and “do not use power against peaceful protesters.”
Ekrem's arrest in March sparked mass protests on the streets of Istanbul, as hundreds of thousands of democracy demonstrators came to support the mayor of Istanbul, who was detained in prison on accusations of corruption he denied.
He said his arrest was political, but the government denied it and insisted that the Turkish courts were completely independent.
The mayor of 2019 Imamoglu is regarded as the only politician capable of challenging Erdogan in the 2028 election. Imamoglu was confirmed as a candidate for the opposition party while he was in custody.
Erdogan has been in power for more than 20 years, first as the Prime Minister, then as president since 2014. He cannot run again for the Presidency after 2028 – unless the Constitution of Turkey has changed.