Security guards stand in front of the United Arab Emirates embassy during its reopening in Damascus, Syria, Dec. 27, 2018. Photo: Reuters / Omar Sanadiki.

The United Arab Emirates reopened its embassy in Damascus on Thursday, marking a big diplomatic boost for President Bashar al-Assad from a US-allied Arab state that once backed rebels fighting him.

The UAE said the move aimed to normalize ties and to curb risks of regional interference in “Arab, Syrian affairs” — an apparent reference to non-Arab Iran, whose support for Assad has been critical to his war effort.

The UAE flag was raised at the embassy, shut since the early months of Syria’s conflict nearly eight years ago. The UAE Foreign Ministry said its charge d’affaires assumed his duties on Thursday.

The UAE was one of several regional states to back armed groups opposed to Assad, though its role was less prominent than those of Saudi Arabia, Qatar or Turkey, rebel sources in the region have said. Emirati support has been associated with groups opposed to Islamist domination of the uprising.

Nearly eight years into the war, Assad has recovered control of most of Syria with support from Russia, Iran, and Iranian-backed Shi’ite Muslim groups such as Lebanon’s Hezbollah.

His military advances gathered pace this year with the defeat of the last big rebel enclaves near Damascus and recovery of the southwestern region.

Earlier this month, Sudanese President Omar al-Bashir became the first Arab head of state to visit Damascus since the start of the Syrian conflict, flying into Damascus airport.

The border crossing between Syria and Jordan, another US-ally that backed the rebels, was reopened in October. A Syrian passenger flight flew to Tunisia on Thursday for the first time in nearly eight years.

The Arab League suspended Syria’s membership in 2011. An Arab diplomat, speaking on condition of anonymity, told Reuters last week he believed a majority wanted Syria to be readmitted — with only three or four states expected to oppose this.

Egyptian state-run media have called for Syria to be reinstated. The secretary general of the Arab League, veteran Egyptian diplomat Ahmed Aboul Gheit, said in April that the decision to suspend Syria had been “hasty.”

Arms, training and funds from Arab states were funneled to Syrian rebels through a program overseen by the CIA until US President Donald Trump ordered it shut down last year. In another potential boost to Assad, Trump also last week decided to withdraw US forces deployed in northern and eastern Syria in support of Kurdish-led militia.

The anti-Assad rebels’ last foothold is an arc of northwestern territory abutting with Turkey, which still supports them.

Damascus has vowed to recoup control of the entire country.