Turkey's president held calls on Syria with his Russian counterpart and Iraq's prime minister, while the top Turkish diplomat is expected to meet with his Russian and Iranian counterparts for three-party talks.

The foreign ministers of Russia, Iran, Turkey and Qatar couldmeet next week to address the recent escalation in Syria, where an Islamist-led rebel alliance seized territory from the control of President Bashar al-Assad's government in a lightning offensive.

Russia has termed the rebel assault as a 'direct violation of Syria's sovereignty', but hinted that it may intervene militarily. Meanwhile, the rebels continue to push forward as they assert control in Aleppo,

Russia has conducted major air strikes on rebels in Syria after insurgents led by the Islamist Hayat Tahrir al-Sham group swept into Aleppo in what is the biggest challenge to its ally President Bashar al-Assad in years.

Russian Foreign Minister Sergei Lavrov discussed on Saturday the escalating situation in Syria with his counterparts from Iran and Turkey, according to the Russian state-run news agency TASS. According to the statement,

A patchwork of rebel forces has seized control of a broad stretch of western and northwestern Syria. It’s unclear how much support weakened allies can provide.

Assad’s regime seemingly came out of nowhere, and as Aleppo fell to Turkish-backed rebels in a matter of days, the Syrian president reportedly flew to Moscow.

Assad, head of the Syrian regime, continued his counter-offensive after insurgents' captured Aleppo last week, vowing to carry on towards the country's capital of Damascus. Both Iran and Russia said they would help al-Assad's government fight back against the Islamist-led offensive,