Feltman said this on Tuesday, while briefing the security council on the UN secretary-general’s fourth report on the threat the group poses to international peace and security efforts to “check and roll it back”.
The UN envoy also noted that Boko Haram was under intense military pressure, but warned against undermining its capacity to launch fatal attacks.
“ISIL-affiliate Boko Haram is attempting to spread its influence and commit terrorist acts beyond Nigeria,” he said.
“And Boko Haram remains a serious threat, with several thousand fighters at its disposal.
“It is, however, plagued by financial difficulties and an internal power struggle, and has split in two factions.”
While the previous reports on the subject had focused on South East Asia, Yemen and East Africa, Libya and Afghanistan, the fourth report focused on Europe, North Africa and West Africa.
It noted that ISIL had conducted a range of attacks in Europe since declaring in 2014 its intent to target the region.
Some of these attacks were directed and facilitated by ISIL personnel, while others were enabled by ISIL providing guidance or assistance or were inspired through its propaganda, it said.
The said while the military offensive in Libya had dislodged ISIL from its stronghold of Sirte, the group’s threat to Libya and neighbouring countries persists.
“Its fighters, estimated to range from several hundred to 3,000, have moved to other parts of the country,” he said.
“ISIL has increased its presence in West Africa and the Maghreb, though the group does not control significant amounts of territory in the region.
“The reported pledge of loyalty to ISIL by a splinter faction of Al-Mourabitoun led by Lehbib Ould Ali may elevate the level of the threat.”
Following the increased military pressure, Feltman said ISIL is now on the defensive militarily in several regions, but was also adapting to military pressure by resorting to covert communications such as the ‘dark web’.
“Although its income and the territory under its control are shrinking, ISIL still appears to have sufficient funds to continue fighting,” he warned.
Feltman noted that ISIL relies mainly on income from extortion and hydrocarbon exploitation, even though resources from the latter are on the decline.
According to him, UN member states are concerned that ISIL will try to expand other sources of income, such as kidnapping for ransom, and increase its reliance on donations.
Feltman said that there were 19 universal counter-terrorism conventions and protocols, as well as related regional instruments on international terrorism, and relevant UN General Assembly and Security Council resolutions.
He warned that foreign terrorist fighters leaving the conflict could pose a grave risk to their homeland or to the countries they are travelling to or transiting through, such as Iraq and Syria’s neighbours, as well as countries in the Maghreb.