Weeks after the US started to sound alarms about a Russian military buildup in Syria, the country’s military, which faces a manpower shortage, has reportedly started using new types of Russian air and ground weapons.

A military source told Reuters in an exclusive report on Thursday that the new weapons “are highly effective and very accurate, and hit targets precisely”. Syrian soldiers were trained in recent months on how to use them, the source reportedly said.

Revelations of the new weaponry come as the Islamic State (IS) group reported on Thursday that it has shot down a MiG-21, a Russian jet, near the Jazal oil field in the Homs governorate.

BREAKING: #ISIS have claimed they have shot down a MiG-21 near #Jazal in #Syria. More info when available. pic.twitter.com/zxTafSJYg4 — Conflict News (@Conflicts) September 17, 2015

The Syrian air force launched heavy air strikes on Thursday on Raqqa, IS's de facto capital which is frequently attacked by the US-led coalition against the group.

The airstrikes on Raqqa are seen as quite rare as government airstrikes have typically targeted cities held by rebel forces.

IS claimed that the strikes killed at least 30 people and injured dozens others, according to Al Jazeera.