After a stopover in Amman, where Florence Parly is set to meet with Jordanian Prime Minister Omar al-Razzaz, she is expected to visit the H5 airbase from which French fighter jets take off for sorties against the jihadists.

The minister's last-minute trip to Jordan comes on the heels of US President Donald Trump's surprise decision in mid-December to pull out all 2,000 American troops stationed in Syria, saying "we've won" against IS.

"The impromptu announcement of the US withdrawal from (Syria) caused a lot of questions," Parly told reporters before landing.

France does not "fully share President Trump's analysis", she said, adding the jihadists were "not quite finished".

"Our priority is to continue until the end."

After sweeping across swathes of Syria and Iraq in 2014, the jihadists' cross-border "caliphate" has been erased by multiple offensives, pushing them back to just a few holdouts in the Syrian desert.

In Syria, IS has been rolled back by separate offensives led by the country's army and an Arab-Kurdish alliance backed by the US-led coalition called the Syrian Democratic Forces (SDF).

The SDF are currently battling to expel the jihadists from their eastern holdout near Syria's border with Iraqi.

Without the help of Washington, which carries out 90 percent of the coalition's strikes on IS, the French government has said it will be difficult to finish the jihadists off for good.

"The United States plays a very important role as leader of the international coalition," said Parly, adding that it might not be "realistic or effective" to continue without Washington.

The French military has deployed 1,200 soldiers as part of the anti-IS efforts, via air operations, artillery, special forces in Syria and training for the Iraqi army.

A ranking French officer said the timeline for the US withdrawal "might not be incompatible" with the capture of the jihadists' remaining territory, "if it is long enough and the (SDF) advance is fast enough".

France will also have to deal with the issue of foreign jihadists, especially Europeans, held by the SDF, now under threat of a looming Turkish offensive to clear Kurdish fighters from its border.

"The US-led coalition has relied heavily on the Kurds as ground operators," said Parly.

"Their fate is of major concern, and there are other questions about the future of a number of prisoners they are holding."