A representative of the Islamic State in Iraq and Syria (ISIS) has told Turkish media that the group plans to seize the Saudi Arabian city of Arar before moving to ruin Islam’s holiest site.

As quoted by the APA news service, ISIS member Abu Turab Al Mugaddasi reportedly said, “If Allah wills, we will kill those who worship stones in Mecca and destroy the Kaaba. People go to Mecca to touch the stones, not for Allah.”

The Kaaba, located in Mecca, Saudi Arabia, is a sacred building at the center of the Al-Masjid al-Haram mosque. Every year, millions of Islamic pilgrims travel to visit the shrine during the hajj, a journey mandated for every Muslim by the Five Pillars of Islam. The Kaaba houses the Black Stone, the eastern cornerstone of the building which Muslims believe is the remnant of a meteorite that fell from Heaven in order to show Adam and Eve where to build the first altar.

The bold threat comes during the Islamic holy month of Ramadan and just days after ISIS seized control of several areas in Iraq and declared a new caliphate straddling Iraq and Syria, prompting an increased U.S. military presence and a delay in the newly elected Iraqi parliament’s first session. It is yet unclear how the threat of violence toward Mecca will impact ISIS’ recent efforts to recruit new members across the region.