The Daesh terrorist group has up to 30,000 members roughly equally distributed between Syria and Iraq and its global network poses a rising threat – as does al-Qaida, which is much stronger in places, a United Nations report said.

The report by U.N. experts circulated Monday said that despite the defeat of Daesh in Iraq and most of Syria, it is likely that a reduced "covert version" of the militant group's "core" will survive in both countries, with significant affiliated supporters in Afghanistan, Libya, Southeast Asia and West Africa.

Member-states told the monitors that the total Daesh membership in Iraq and Syria was "between 20,000 and 30,000 individuals, roughly equally distributed between the two countries." "Among these is still a significant component of the many thousands of active foreign terrorist fighters," said the report.

The sanctions monitoring team submits independent reports every six months to the Security Council on Daesh and al-Qaida, which are on the U.N. terrorist blacklist.

By January 2018, Daesh was confined to small pockets of territory in Syria, although the report said the group "showed greater resilience" in eastern Syria. Daesh "is still able to mount attacks inside Syrian territory. It does not fully control any territory in Iraq, but it remains active through sleeper cells" of agents hiding out in the desert and elsewhere, said the report.

Daesh fighters swept into Iraq in the summer of 2014 and took control of nearly a third of the country. At the height of the group's power its self-proclaimed caliphate stretched from the edges of Aleppo in Syria to just north of the Iraqi capital, Baghdad.

With its physical caliphate largely destroyed, the Daesh movement is transforming from a "proto-state" to a covert "terrorist" network," a process that is most advanced in Iraq" because it still controls pockets in Syria, the report said. The experts said the discipline imposed by Daesh remains intact and Daesh leader Abu Bakr al-Baghdadi "remains in authority" despite reports that he was injured. "It is just more delegated than before, by necessity, to the wider network outside the conflict zone," the experts said.

The flow of foreign fighters to Daesh in Syria and Iraq has come to a halt, they said, but "the reverse flow, although slower than expected, remains a serious challenge."

While the rate of terrorist attacks has fallen in Europe, the experts said some governments "assess'' that the underlying drivers of terrorism are all present and perhaps more acute than ever before." This suggests that any reduction in attacks is likely to be temporary until Daesh recovers and reorganizes and al-Qaida "increases its international terrorist activity or other organizations emerge in the terrorist arena," they said.