The report by UN sanctions monitors estimates that between 3,000 and 4,000 Daesh terrorist were based in Libya while some of the key operatives in the extremist group were being relocated to Afghanistan.

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-Qaeda, which are on the UN terrorist blacklist.

Daesh once controlled large swathes of territory in Iraq and Syria, but last year it was driven out of Mosul and Raqqa.

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.

The flow of foreigners leaving Daesh "remains lower than expected" and no other arena has emerged as a favourite destination for foreign fighters, although "significant numbers have made their way to Afghanistan", said the report.

There are estimated 3,500-4,500 Daesh fighters in Afghanistan and those numbers are increasing, according to the report.

The flow of foreign fighters toward Daesh "has essentially come to a halt", it added.

Daesh commands only 250 to 500 members in Yemen, compared to between 6,000 and 7,000 fighters for Al Qaeda.

In the Sahel, Daesh in the Greater Sahara is active mostly at the border between Mali and Niger but has less of a foothold than the Al Qaeda-linked Jamaat Nusrat Al Islam wal-Muslimin.

The Al Qaeda-linked Shabaab dominates in Somalia but the report said that Daesh "has the strategic intent to expand to central and southern Somalia". Some Somali Daesh fighters may choose to relocate to Puntland, said the report.