The statement comes as questions are raised over whether Washington was encouraging and supporting a rapprochement between Jordan and Syria after Jordan fully reopened its border-crossing with its neighbour.
The US has no plans to "normalise or upgrade" diplomatic relations with the Syrian regime leader Bashar al Assad and also does not encourage others to do so, a State Department spokesperson has said.
The comments came in response to Reuters questions on whether Washington was encouraging and supporting a rapprochement between Jordan and Syria after Jordan fully reopened its main border crossing with Syria on Wednesday.
The move was to boost the countries' struggling economies and reinforce a push by Arab states to reintegrate Syria after shunning it during its civil war.
"The United States will not normalise or upgrade our diplomatic relations with the Assad regime nor do we encourage others to do so, given the atrocities inflicted by the Assad regime on the Syrian people," a State Department spokesperson said in an email.
"Assad has regained no legitimacy in our eyes, and there is no question of the US normalising relations with his government at this time."
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Strongest comments to date
It was among the strongest comments to date on Syria from the Biden administration, whose Syria policy has largely focused on ensuring the permanent defeat of Daesh and providing humanitarian aid to Syrian people.
The United States has suspended its diplomatic presence in Syria since 2012.
The Trump administration last June imposed its most sweeping sanctions ever targeting Assad and his inner circle to choke off revenue for his government in a bid to force it back to United Nations-led negotiations and broker and end to the country's decade-long war.
Arab states cut ties with Syria during the civil war, which the UN says killed at least 350,000 people, and US-allied Arab states, including Qatar, Saudi Arabia and the United Arab Emirates backed opposition groups fighting Assad.
The United Arab Emirates and Syria restored diplomatic ties in 2018.
The Egyptian and Syrian foreign ministers met on Friday on the sidelines of the UN General Assembly in New York, in what Egyptian media said was the first meeting at that level for about a decade.
Officials in Jordan, a US ally, and Lebanon have urged Washington to ease sanctions on Syria.
"We believe that stability in Syria, and the greater region, can only be achieved through a political process that represents the will of all Syrians and we are committed to working with allies, partners, and the UN to ensure that a durable political solution remains within reach," the State Department spokesperson said.
Assad has recovered most of Syria but some areas remain outside his control.