The Syrian capital Damascus witnessed a large explosion at a missile stockpile site belonging to pro-Iranian militias on the outskirts of the city on Sunday, a war monitoring group reported.

The Syrian Observatory for Human Rights (SOHR), an organization based in the UK that maintains a network of sources within Syria, said that residents in the Damascus region heard powerful blasts originating from "warehouses of pro-Iranian militias."

Syria's official news agency SANA also reported "sounds of explosions" on the eastern outskirts of the capital city.

"We don't know if it was from an airstrike or ground operation," SOHR head Rami Abdel Rahman told AFP.

Strikes in Syrian territory

Iran has been one of the most important supporters of President Bashar Assad's regime, especially during the 12-year-long civil war that has torn the country apart.

Iranian forces stationed in Syria have been targeted by Israeli strikes in the past amid fears that Israel's main rival in the region is trying to spread its influence. Pro-Iran groups, including Lebanon's Hezbollah, dominate several parts of the Syrian capital.

Iran also supports Islamist militant groups in the occupied West Bank and Gaza.

Last week, Syrian state media said that Israel was behind an airstrike that killed at least four Syrian soldiers around Damascus. SOHR said the strikes had targeted Iran-backed militias.

Although Israel has vowed to prevent Iran from establishing itself in Syria and Lebanon, it rarely claims responsibility for strikes in those countries.

Assisted by Russia and Iran, the Assad regime has managed to regain a substantial portion of the territory that was initially lost to rebel groups in the early stages of the conflict, which began in 2011.

The ongoing war in Syria has led to the loss of over half a million lives and the displacement of millions more.

tg/ab (AFP, AP, Reuters)