Iran is establishing a permanent military base inside Syria, a Western intelligence source has told the BBC.
The Iranian military is said to have established a compound at a site used by the Syrian army outside El-Kiswah, 14 km (8 miles) south of Damascus.
The report comes amid growing tensions over Iranian influence in Syria and across the region.
Israeli PM Benjamin Netanyahu recently warned that Iran wanted to establish itself militarily in Syria.
“Israel will not let that happen,” he said.
Satellite images commissioned by the BBC seem to show construction activity at the site referenced by the intelligence source between January and October this year.
The images shows a series of two dozen large low-rise buildings – likely for housing soldiers and vehicles.
In recent months, additional buildings have been added to the site. However, it is impossible to independently verify the purpose of the site and the presence of the Iranian military.
An official from another Western country told the BBC that ambitions for such a long-term presence in Syria would not be illogical for Iran.
Its adversaries have accused Iran of seeking to establish not just an arc of influence but a logistical land supply line from Iran through to the Shia Hezbollah movement in Lebanon.
With so-called Islamic State (IS) suffering major defeats on the battlefield and losing its last strongholds, attention is increasingly turning to what comes next and the new map of power and influence in Syria.
Iran has been a consistent backer of the regime of President Bashar al-Assad. Photographs published on social media in the past few days also showed a senior Iranian general in Deir al-Zour shortly after IS was driven out of the town.
The photos show Maj Gen Qasem Soleimani, head of the Quds force of the Islamic Revolution Guards Corps (IRGC) alongside members of a militia.
With a significant number of IRGC fighting – and in some cases…