Syrian rebel advance poses risks for U.S. and others, former envoy says

By Jonathan Spicer

A rapid rebel advance in northwest Syria poses risks for the United States, which was "caught unaware", and other countries including Turkey, Russia and Iran, former U.S. ambassador James Jeffrey told Reuters.

Jeffrey, former U.S. Ambassador to the Coalition to Defeat Islamic State under the previous Trump Administration, said President-elect Donald Trump was likely to ramp up pressure on Syria's ally Iran both there and across the region.

The rebels' capture of Aleppo and Hama dealt a blow to President Bashar al-Assad, nearly 14 years after protests against him erupted across Syria.

"Such a dramatic change in the balance of power in Syria makes everybody nervous because everybody has a chunk of Syria," said Jeffrey, a former envoy to both Turkey and Iraq who chairs the Washington-based Wilson Center's Middle East Program.

"We were caught unaware. You only have so much in terms of intelligence assets... and we basically prioritise," he said of the U.S. in a telephone interview late on Thursday.

Some 900 U.S. troops are stationed mainly in Syria's northeast in support of their Kurdish allies, the Syrian Democratic Forces, following a U.S. intervention in 2014.

Asked about policy changes when Trump returns to the White House next month, Jeffrey said Trump's statements and record suggested he would "aggressively contest Iran throughout the region."

U.S. National Security Advisor Jake Sullivan said this week it was no surprise that rebels would try to take advantage of the situation in which Assad's main backers - Iran and Russia - were distracted and weakened by conflicts elsewhere.

NATO member Turkey, Russia and Iran have troops in Syria. The rebels include some Turkey-backed groups and are spearheaded by Hayat al-Tahrir al-Sham, which Ankara and Washington deem terrorists.

HTS has primarily driven south towards the city of Homs. U.S.-backed Kurdish forces abandoned positions in Aleppo and Tel Refaat in the face of the initial offensive in the north.