The People's Mojahedin Organization of Iran, an organized resistance in the country, said Tuesday that members clashed with the Islamic Revolutionary Guard Corps around Ayatollah Khamenei's headquarters in Tehran, resulting in the death or arrest of more than 100 of the resistance fighters.

More than 150 of the Mojahedin fighters who had participated in the storming of the headquarters on Monday safely returned to their bases, according to PMOI/MEK. The names of the more than 100 fighters who were killed, wounded, or arrested will be released to international human rights organizations.

"Enemy casualties inside Khamenei’s headquarters are reported to be heavy, but no precise figures are available. Ambulance traffic into the compound, escorted by special units, continued until noon on Monday," PMOI/MEK said.

There appears to be no independent mainstream reporting on the clash.

During protests in Iran last month, as many as 30,000 people were killed, two unnamed senior officials from the Iranian Ministry of Health told TIME. The death toll far exceeded the 3,117 announced by the Iranian regime. Also in January, the Human Rights Activists News Agency said it had confirmed 5,459 deaths and was investigating 17,031 more. The media outlet was unable to independently verify the figures.

“A few minutes ago, several users reported hearing the sound of explosions in Tehran,” the regime-affiliated Momtaz News website said when it first reported the explosions at 6:00 a.m. Monday local time, according to PMOI/MEK. Simultaneous attacks on Khamenei’s residence and the Supreme National Security Council in the Pasteur district of Tehran were later reported by the Arya News Agency, per the resistance group.

The IRGC-run Bultan News wrote at 11:50 a.m. Monday, per PMOI/MEK, "The repeated sounds of explosions last night in the Pasteur Street area, the most secure district of the capital, have raised a serious question among all officials and those concerned about the system. What has happened to us that the enemy now covets the heart of Tehran and dares to reach out toward it?"

“Under such circumstances, none of us has the right to pass even a single night in comfort — let alone allow the enemy to dare, in the most sensitive point of the capital, Pasteur Street, to carry out explosions and gunfire and challenge our devoted forces,” the outlet later added.