The US promised Wednesday (February 6th) to stay focused on permanently destroying the "Islamic State of Iraq and Syria" (ISIS), as President Donald Trump said that the extremists will soon have lost all their territory in Syria.

Trump addressed officials from more than 70 countries who came to Washington to discuss ways ahead in the battle against ISIS, AFP reported.

Speaking at the State Department, Trump said that US-led troops and their Kurdish allies had "liberated virtually all of the territory" from the extremists who once controlled a vast stretch of Syria and Iraq.

"It should be formally announced some time next week that we will have 100%" of ISIS's territory, Trump said.

"Remnants -- that is all they have, remnants -- but remnants can be very dangerous," Trump said.

"Rest assured, we will do what it takes to defeat every ounce and every last person within the ISIS madness and defend our people from radical Islamic terrorism," he said.

German Foreign Minister Heiko Maas voiced approval that Trump made clear that his troop withdrawal from Syria "does not mean that the US will no longer take on its leading role in the fight against ISIS".

"Now it is important that in the upcoming weeks that we talk about how this will be organised and who will take on which tasks," Maas told reporters.

Meanwhile, a report by the UN sanctions monitoring team presented to the Security Council Wednesday revealed that there are between 14,000 and 18,000 ISIS militants in Syria and in Iraq, including up to 3,000 foreign fighters.

ISIS leadership has been reduced to a dispersed group and "is directing some fighters to return to Iraq to join the network there" with the aim "to survive, consolidate and resurge in the core area", said the report.

"If successful, ISIS may be expected to revive its focus on external terrorist operations, but for now the ISIS core lacks the capability to direct international attacks," it added.

The report by the UN analysts draws mostly on information provided by UN member states and covers the period from July to December 2018.