According to Turkey's General Directorate of Security, a total of 339 protesters have been detained under a new security law and 50 people, including 25 police officers, injured across Turkey amid May Day protests.
Four of the detainees were later charged in an Istanbul court with being members of an illegal organization.
The directorate said in a written statement on Saturday: "During demonstrations across Turkey, 25 policemen and 25 other civilians were injured."
The statement also said judicial proceedings against demonstrators who were detained were continuing.
The legal process is being carried out under a newly passed controversial domestic security law which was passed by the Turkish Parliament’s General Assembly on March 27 and approved by President Recep Tayyip Erdogan on Friday.
The domestic security package consists of 69 articles under which Turkish police are allowed to use weapons against those who attack schools, public buildings and places of worship with Molotov bombs, explosives, inflammable materials and other weapons.
At least 10,000 police were on duty in Istanbul while 7,000 other were in Ankara as a part of security measures taken on Labor Day.
Labor Day demonstrations in Istanbul's Taksim Square in 1977 led to the deaths of 34 people and the wounding of 136 in what became known as Bloody May 1.
Union activists have been barred from marching to the public square since 2013.