Security measures were elevated in Istanbul and other big cities Sunday as several groups that sided with the PKK terrorist group announced that they would rally to mark a traditional Turkic festival.

The festivities of Nevruz, a festival commonly celebrated by Turkic countries to mark the arrival of spring, have long been exploited by the terrorist group tying it to Kurdish traditions. Nevruz celebrations in the past years have long been the ground for clashes between PKK supporters and security forces.

The Peoples' Democratic Party (HDP), a political party known for its ties to the terrorist group, had announced that they would celebrate the event in Istanbul's Bakırköy district yesterday, but the governorate did not allow them. Turkey will formally celebrate Nevruz tomorrow, and the HDP will be allowed to organize its own festival in southeastern Turkey tomorrow. However, the party and other groups affiliated with the PKK had long planned to mark it yesterday to attract a larger crowd.

No demonstrators showed up in the main square in Bakırköy, as police kept a close watch on the streets leading to the square and shut down the nearby metro station. The HDP and other groups have defied the bans on rallies not in line with the formal schedule in past years, but it apparently did not do so this year. A Nevruz rally organized by the HDP is scheduled to go ahead in the southeastern city of Diyarbakır as local authority gave them the green light for tomorrow.

Nevruz is also the time of the spring thaw in which PKK militants hiding out in mountainous territory in northern Iraq have infiltrated Turkey in the past, and the terrorist group in general, increase its attacks after a lull in the winter months.