Syrian President Bashar al-Assad's visit to the United Arab Emirates left the US "profoundly disappointed", it said Saturday, urging allies to avoid normalising ties with a regime accused of "horrific atrocities".
Assad's surprise trip on Friday was his first official visit to an Arab country since civil war erupted in his country in 2011, killing close to half a million people.
It was the latest sign of warming relations between Syria and energy-rich UAE -- a key US ally which also normalised ties with Israel in 2020.
"We are profoundly disappointed and troubled by this apparent attempt to legitimise Bashar al-Assad," US State Department spokesman Ned Price said in a statement sent to AFP on Saturday.
Assad, he said, "remains responsible and accountable for the death and suffering of countless Syrians, the displacement of more than half of the pre-war Syrian population, and the arbitrary detention and disappearance of over 150,000 Syrian men, women and children.
As US Secretary of State Antony "Blinken has reiterated, we do not support efforts to rehabilitate Assad, and we do not support others normalising relations," Price said.
"We have been clear about this with our partners... (and) we urge states considering engagement with the Assad regime to weigh carefully the horrific atrocities visited by the regime."
Friday's visit by Assad to the UAE came as Russia -- a key Damascus backer which also has solid ties with the Emirates -- pressed its war on Ukraine.
- 'Fraternal' ties -
Syria's war erupted in March 2011 after the brutal repression of anti-government protests, and a year later the UAE, like most Arab countries, broke ties with Damascus.
But the UAE reopened its embassy in the Syrian capital in December 2018, suggesting an effort to bring Assad's regime back into the Arab fold.
On Friday, Assad and Abu Dhabi Crown Prince Sheikh Mohammed bin Zayed Al-Nahyan, the UAE's de facto ruler, discussed the "fraternal relations" between the two countries, the official news agency WAM reported.
Talks also centred on efforts to "contribute to the consolidation of security, stability and peace in the Arab region and the Middle East", said WAM.
Sheikh Mohammed said he hoped the visit would "pave the way for goodness, peace and stability to prevail in Syria and the entire region", it added.
The pair also discussed ways of "preserving the territorial integrity of Syria and the withdrawal of foreign forces from the country," it said, as well as means of providing "political and humanitarian support for Syria".
Syria's state news agency SANA said the meeting had helped to "strengthen cooperation" between the two sides.
Photographs released by Syria's presidency showed Assad also meeting with Dubai's ruler, Sheikh Mohammed bin Rashid Al-Maktoum, during the one-day visit.
- Russia, Syria and the Gulf -
Syria's complex war drew in numerous players, including jihadists and foreign players such as Iran and Russia, and battered its economy.
In September 2015, Russia began launching air strikes in support of Syria's regime, a turning point in the conflict that eventually helped Assad regain control of most of the country.
Assad has praised the invasion Russia launched against Ukraine on February 24 as a "correction of history".
The UAE hosts American troops and has been a strategic partner to the United States for decades, but its economic and political ties with Russia are growing.
The UAE and Saudi Arabia, two of the world's biggest oil exporters, have so far avoided taking a position against Russia.
Russia's war on Ukraine has impacted Gulf-US relations, experts say, as oil giants like the UAE and Saudi Arabia resist appeals by Washington and other Western capitals to raise oil output in a bid to rein in prices.
Last year, the UAE called for Syria's return to the Arab League, which had suspended its membership after the onset of the war.
And in November, the UAE's top diplomat met Assad in Damascus for the first time since the conflict started, a move slammed by the US.
Syria's war has killed about half a million people, displaced millions and devastated its infrastructure.
A UN commission of inquiry this month called for "a review of the implementation and impacts of sanctions currently imposed on Syria" in light of deteriorating living conditions.
But State Department spokesman Price said on Saturday that the US would maintain sanctions on Syria "until there is irreversible progress toward a political solution".