Syria will join the international coalition formed to fight the Islamic State (IS) group, a senior Trump administration official has confirmed.

The agreement is said to be a major shift in US Middle East policy.

The decision was announced during a meeting between US President Donald Trump and Syrian President Ahmed al-Sharaa at the White House. It is the first visit by a Syrian leader in US history.

In an interview with Fox News, the Syrian president said the visit was part of a "new era" of cooperation between Syria and the United States.

Trump, for his part, expressed his support for the new Syrian President, al-Sharaa, who until recently was on the US government's terrorist list.

Under the decision, Syria will become the 90th country to join the international coalition formed to defeat ISIS.

The coalition aims to eliminate the remaining members of the so-called Islamic State group and to stop the flow of foreign fighters to the Middle East.

In addition, a senior official said that US government agencies will announce new steps to lift economic sanctions on Syria and provide "compliance clarifications to investors" regarding the country's laws and practices.

"We want to see Syria as a very successful country," Trump told reporters at the White House after the meeting.