Rubio says Syria could be weeks away from 'full-scale civil war'

US Secretary of State Marco Rubio warned Tuesday that Syria could be weeks away from a fresh civil war of "epic proportions," as he called for support to the transitional leadership.

The top American diplomat blamed a resurgence of the Islamic State extremist group in areas outside of the transitional government's control, as well as Iran.

He told a US Senate hearing that the government, "given the challenges they're facing, are maybe weeks - not many months - away from potential collapse and a full-scale civil war of epic proportions, basically the country splitting up."

Rubio spoke after a series of bloody attacks on the Alawite and Druze minorities in Syria, where Islamist-led fighters in December toppled then-president Bashar al-Assad, capping a brutal civil war that began in 2011.

US President Donald Trump last week on a visit to Saudi Arabia announced a lifting of Assad-era sanctions and met with the guerrilla leader who is now Syria's transitional president, Ahmed al-Sharaa.

Sharaa, clad in a suit and complimented by Trump as a "young, attractive guy," was until recently on a US wanted list over jihadist connections.

Rubio quipped: "The transitional authority figures, they didn't pass their background check with the FBI."

But he added: "If we engage them, it may work out, it may not work out. If we did not engage them, it was guaranteed to not work out."

Rubio, who also met with Syria's foreign minister in Turkey on Thursday, said Iran was looking to work with remnants of the fallen ally Assad, who hailed from the Alawite sect.

Rubio acknowledged concerns about Syria's direction in Israel, which has kept pounding military sites in the neighbouring country.

But Rubio, who has spoken twice in recent days to Israeli Prime Minister Benjamin Netanyahu, said a more stable Syria that did not serve as a "launchpad for attacks" would be an "extraordinary achievement for Israel's security."