ISTANBUL — Police in Turkey have detained dozens of people for chanting slogans or unfurling banners in support of outlawed Kurdish rebels during celebrations marking the start of spring.

Festivities were held Wednesday in Istanbul, in the mainly Kurdish city of Diyarbakir and in several other towns and cities across Turkey, under tight security. Kurds traditionally use the March 21 festival, known as Newroz, to assert their ethnic identity and demand greater rights.

The state-run Anadolu Agency said 22 demonstrators were detained in Istanbul for alleged “propaganda” supporting the rebels and a Kurdish faction in Syria that Ankara also considers as terrorists.

At least 26 others were detained in Izmir and Adana, the agency reported. Police also broke up an unauthorized demonstration in the mainly Kurdish city of Batman.