Nationwide protests over the death of a young Iranian Kurdish woman in the custody of Iran's morality police have been at their most intense in the northwestern areas where the majority of the country's 10 million Kurds live.
The protests, now in their fourth week as demonstrators defy a crackdown by security forces, pose the biggest challenge to Iran's clerical rulers in years.
The demonstrations began in reaction to the death of 22-year-old Mahsa Amini and then spread to every one of Iran's 31 provinces.
The death of the ethnic Kurd raised tensions between the establishment and Iran's Kurdish minority, which human rights groups say have been long oppressed by Iran's leadership.
The Islamic Republic denies persecuting Kurds.
Tehran has blamed Kurdish dissident groups and foreign enemies for fomenting some of the protests, and its armed forces responded to the turmoil by striking Iranian Kurdish opposition groups inside neighbouring Iraq.
The elite Revolutionary Guards have put down unrest in the Kurdish community for decades, and the country’s judiciary has sentenced many activists to long jail terms or death.
Here are some facts about Iran's Kurds, part of a community that is spread across several Middle East countries and one of the world's largest people without a state.
HISTORY
Minority Kurds, mainly Sunni Muslims in Shi'ite-dominated Iran, speak a language related to Farsi and live mostly in a mountainous region straddling the borders of Armenia, Iraq, Iran, Syria and Turkey.
Kurdish nationalism stirred in the 1890s when the Ottoman Empire was on its last legs. The 1920 Treaty of Sevres, which imposed a settlement and colonial carve-up of Turkey after World War One, promised Kurds independence. Three years later, Turkish leader Kemal Ataturk tore up that accord.
The Treaty of Lausanne, ratified in 1924, divided the Kurds among the new nations of the Middle East.
Kurdish separatism in Iran first bubbled to the surface with the 1946 Republic of Mahabad, a Soviet-backed state stretching over Iran’s border with Turkey and Iraq. It lasted one year before the central government wrested back control.
Iran's 1979 Islamic Revolution touched off bloodshed in its Kurdistan region with heavy clashes between the Shi'ite revolutionaries and the Kurdish Party of Iranian Kurdistan (KDPI) which fought for independence.
After the 1980 eruption of the Iran-Iraq war, regular Iranian armed forces and Revolutionary Guards doubled down on their repression of Kurds so as to prevent them becoming a fifth column in Tehran’s fight against Saddam Hussein.
New militant groups such as the Kurdistan Free Life Party (PJAK) have emerged over the past two decades and have occasionally clashed with security forces. Their leaders have often sought refuge in Iraqi Kurdistan and have been attacked by Iranian missiles.
Kurdish claims have oscillated between full-on separatism and autonomy within a multi-ethnic Iranian state, spanning a wide political spectrum from left-leaning secularism to right-wing Islamist thought.
SOCIETY
With eight million to 10 million Kurds living in Iran, Tehran fears pressure for secession will grow among a minority with a long history of struggle for its political rights.
Rights groups say Kurds, who form about 10 percent of the population, along with other religious and ethnic minorities face discrimination under Iran's Shi'ite clerical establishment.
"Kurds in Iran have long suffered deep-rooted discrimination. Their social, political and cultural rights have been repressed, as have their economic aspirations," human rights group Amnesty International said in a report.
"Kurdish regions have been economically neglected, resulting in entrenched poverty. Forced evictions and destruction of homes have left Kurds with restricted access to adequate housing."
(Writing by Michael Georgy, Editing by William Maclean)