Mussa Babakhani, a member of the central committee of the Kurdistan Democratic Party of Iran (KDPI), was "assassinated by a terrorist affiliated" with Iran, a statement from the party said.

Tehran refers to the KDPI, which is based in Iraq's autonomous Kurdistan region, as a "terrorist" group.

Babakhani was "kidnapped Thursday by two terrorists and found dead and bearing marks of torture" on Saturday in a hotel room in Arbil, the capital of Iraqi Kurdistan, the statement said.

Kurdish security forces have said they are investigating his death.

The KDPI accuses Iran of murdering several of its leaders in recent years. It said Babakhani, born in 1981, joined the party in 1999.

The group was banned after Iran's 1979 Islamic revolution.

In September 2018, an Iranian missile strike on the KDPI headquarters in Iraq's Kurdish region killed 15 people.

In July 2019, Iran's Revolutionary Guards said they had attacked suspected "terrorists" in Iraqi Kurdistan, killing and wounding several.

Kurds, a non-Arab ethnic group, have long agitated for their own state. They number between 25 million and 35 million people and are spread across Turkey, Syria, Iraq and Iran.

In Iran, they make up around 10 percent of the population.

Tehran has warned the authorities in Iraqi Kurdistan not to allow "terrorist groups" to set up camps near the border.