U.S. Secretary of State Mike Pompeo speaks with the press as he flies to the Middle East on January 7, 2019. (Photo: VCG)

US Secretary of State Mike Pompeo vowed Monday that the Islamic State group would not be allowed to regroup as he headed to the Middle East following President Donald Trump's surprise decision to pull US troops from Syria.

Leaving on a trip to eight Arab capitals, Pompeo told reporters he would show that "the United States is still committed to all the missions that we've signed up for with them over the past two years."

The trip comes weeks after Trump announced that the United States would quickly pull its 2,000 soldiers out of Syria, declaring that the Islamic State group, also known as ISIS or IS, had been defeated.

His advisers have since been walking back his timeline, with national security adviser John Bolton saying Monday in Jerusalem that the United States would verify that the group is truly defeated before withdrawing.

Highlighting that IS emerged during the tenure of Trump's predecessor Barack Obama, Pompeo said the campaign to destroy the movement's self-styled caliphate in war-battered Syria has been "enormously successful."

"And I am confident that we will continue to ensure that the kind of rise that ISIS had under the Obama administration doesn't occur again," he said on his plane as he started his longest trip since taking over as top US diplomat last year.