At least 164 people were detained during unauthorized demonstrations to mark Nevruz in Istanbul Sunday, according to Turkish security sources.
Nevruz celebrations were banned across Turkey due to security concerns amid fresh counter-terrorism operations in the southeast.
In Istanbul, police intervened when groups burnt tires and attacked security personnel with fireworks and Molotov cocktails during demonstrations in several districts of the port city.
Out of the 164 people held, 12 were under 18 years of age.
Police also said they seized 152 Molotovs, inflammable materials, improvised explosive device materials, construction work gloves and balaclavas.
Police also detained 44 people between Friday and Saturday during Nevruz-related demonstrations; 15 of them were formally arrested.
Nevruz marks the beginning of spring and has been celebrated in many parts of the world, including the Balkans, the Black Sea, the Caucasus, and most parts of Asia, including Iran for hundreds of years.
Last Wednesday, local officials in the country's southeastern provinces of Mus, Batman, Bingol, Tunceli and Sirnak said Nevruz restrictions would be imposed due to security reasons.
The PKK - listed as a terrorist organization by Turkey, the U.S. and EU - resumed its 30-year armed campaign against Turkey in July. Since then, more than 300 members of the security forces have been martyred and thousands of terrorists killed.