Iran has vowed "a severe response" over the mass killing.
Iran's leaders vowed Thursday to "punish" those behind a shooting that killed 15 worshippers at a Shiite Muslim shrine, as security forces pushed on with their deadly crackdown against women-led protests.
In the latest violence, a rights group said, security forces killed a Kurdish man when protesters massed around government buildings in western Iran, a flashpoint area in almost six weeks of unrest sparked by the death of Mahsa Amini in police custody.
As thousands mourned 22-year-old Amini on Wednesday, Iran was also rocked by an attack claimed by the Islamic State jihadist group in which, state media said, a gunman killed at least 15 people at a shrine in the southern city of Shiraz.
Ultra-conservative President Ebrahim Raisi appeared to link the two tragedies when he declared that "the intention of the enemy is to disrupt the country's progress, and then these riots pave the ground for terrorist acts".
Iran's embassy in India released a video of the attack, saying, "This is the real face of terrorism against Iranian people which the world is silent on it. The video clip [is] of yesterday's brutal terrorist attack against civilians in Iran."
Raisi has vowed "a severe response" over the mass killing at the Shiite Muslim Shah Cheragh mausoleum following evening prayers.
Supreme leader Ayatollah Ali Khamenei called for united efforts against the "plot" by Iran's enemies. "The perpetrator or perpetrators of this saddening crime will certainly be punished," he said.
Iran has been gripped by its biggest protests for years since Amini died on September 16, three days after her Tehran arrest by the notorious morality police for allegedly breaching the country's dress code for women.
The latest protests in the west follow a massive ceremony Wednesday marking 40 days since Amini's death, held in her hometown of Saqez, Kurdistan province.
Iran's ISNA news agency said nearly 10,000 people had gathered there, but many thousands more were seen making their way in cars, on motorbikes and on foot, in videos widely shared online.
