The US official travelled to Damascus via Lebanon and discussed security matters with Syrian counterparts, Reuters reports
A senior US official met Syria's national security chief in Damascus this week, a senior regional official close to Damascus told Reuters on Friday.
This is the highest ranking visit to Syria by a US official since the start of the civil war in 2011.
The Lebanese newspaper al-Akhbar first reported the visit earlier on Friday, saying that the US official discussed security matters, including Americans missing in Syria. Among them are operatives of the Central Intelligence Agency (CIA).
The regional official did not identify the US official who met Ali Mamlouk, Syria's national security chief. "It is an important step, but Damascus does not have confidence in the American position," the regional official said.
The US official travelled to Damascus via Lebanon.
Al-Akhbar, which is close to Hezbollah and Damascus, said the US official expressed Washington’s lack of trust in armed opposition groups to hold territories and ensure stability.
The United States has supported the opposition to President Bashar al-Assad's government during the Syrian war. It has provided anti-Assad rebels with weapons via a CIA-run military aid programme that President Donald Trump ordered shut down earlier this year.
Iranian official said government forces would advance soon to take Raqqa city, which is held by US-backed fighters (Reuters)
US Secretary of State Rex Tillerson last week reiterated the US position that Assad should leave power, saying the "reign of the Assad family is coming to an end" and "the only issue is how that should be brought about".
With military backing from Russia and Iran, Syrian government forces have recovered control of swathes of lost Syrian territory over the last two years and appears militarily unassailable.
US forces have been fighting in Syria as part of the coalition against the Islamic State (IS) group, helping Kurdish-led militias capture Raqqa and other parts of northern and eastern Syria.
During the meeting, Mamlouk protested to the US official that US forces "are on Syrian land and this is considered occupation," the regional official said. The US official responded that "our presence is advisory and we are fighting Daesh," the regional official added, using an Arabic acronym for IS.
Meanwhile, a senior Iranian official said that Syrian government forces would advance soon to take Raqqa city, which US-backed fighters seized from IS last month.
Ali Akbar Velayati, the top adviser to Iran's Supreme Leader, also accused the United States of seeking to divide Syria in two by stationing itself east of the Euphrates river.
"We will witness in the near future the advance of government forces ... in Syria and east of the Euphrates, and the liberation of Raqqa city," he said in televised comments on a visit to Beirut on Friday.