A series of explosions of an unknown origin rocked northwestern Syria near the city of Hama, late Sunday night, Syrian media reported.

According to the Orient news outlet, which is affiliated with the Syrian rebels, the blasts occurred in a base belonging to the Syrian army’s 47th Brigade, which is being used by Iran-backed Shiite militias.

The base is located just south of Hama. The facility was said to house a weapons depot, which accounted for the size and intensity of the blast, which could be seen from kilometers away and reportedly registered on seismographs in the area.

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Syrian state media reported that authorities were working to “determine the cause of the explosions.”

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The Orient news outlet noted that the base was known to be the headquarters of Iranian militiamen and had been “heavily involved” in attacks against rebel forces in the area.

Some on social media speculated that the alleged Iranian facility had been hit in an Israeli airstrike. As a rule, the Israeli Air Force does not comment on its activities abroad.

Videos of the blast show a fireball lighting up the night sky.

فيديو للإنفجارات في ريف حماه ..نسأل الله السلامة للرجال هناك ..????الشفاء العاجل للجرحى ..حتى الآن لم يصرح مصدر مسؤول عن ماهية الإنفجارات ..#محردة_الآن Posted by ‎محردة الآن‎ on Sunday, 29 April 2018

Earlier Sunday, Defense Minister Avigdor Liberman said Israel would preserve its ability to act all over Syria against any threats, and would not be deterred if Russia supplies the Syrians with advanced air defense systems.

He added that Israel would stop at nothing to prevent Iran from using Syrian territory as a base to attack Israel.

“We will maintain freedom of operation in all of Syria,” Liberman said, when asked about Russia equipping Syria with advanced systems.

Israel has repeatedly voiced concerns that, as well as trying to deliver advanced weaponry to the Lebanese terror group Hezbollah, Iran has been using the unrest in Syrian as a means to establish forward operating bases that could be used to launch rocket attacks and other military action against Israel.

Israel, Liberman said, “will prevent Iran from establishing a forward base in Syria at any cost.”

Stuart Winer contributed to this report.