(CNN) ISIS has begun reasserting itself in Iraq and Syria under a new leader assessed to be an Iraqi operative who was a driving force behind the terror group's genocide against the Yazidi people, according to a report submitted to the UN Security Council which was made public on Wednesday.

The wide-ranging report, compiled by the UN Monitoring Team that tracks the global jihadi terror threat, refers to the group by its alternate name stating the "Islamic State in Iraq and the Levant (ISIL), following its loss of territory, has begun to reassert itself in both the Syrian Arab Republic and Iraq, mounting increasingly bold insurgent attacks, calling and planning for the breakout of ISIL fighters in detention facilities and exploiting weaknesses in the security environment of both countries."

It has been clear for some time that one reason for ISIS's resilience is its deep pockets, with overheads reduced now the group no longer administers a large state . The report said that according to one of the more conservative assessments by UN member states, ISIS still has $100 million in reserves.

"The period from July to September 2019 saw an acceleration of the reconstitution of ISIS as a covert network in the Syrian Arab Republic, mirroring what had happened in Iraq since 2017. Freed of the responsibility of defending territory, there was a notable increase in attacks in previously quiet areas held by the Government of the Syrian Arab Republic around the country," the report stated.

The report noted: "The borders between Iraq and the Syrian Arab Republic remain inadequately secured, allowing some movement of fighters between both jurisdictions. Recent developments east of the Euphrates have led to an increase of ISIL activity in Dayr al-Zawr and Hasakah Governorates and a spike in attacks targeting the United States led coalition and local non-State armed groups."

New leader

The report, which is based on information from UN member states, revealed that several of those states assess the new leader of ISIS is Amir Muhammad Said Abdal Rahman al-Mawla, Abu Bakr al-Baghdadi's deputy. It cautions the information has not yet been confirmed.

For months mystery surrounded the real identity of ISIS's new leader. A few days after Abu Bakr al-Baghdadi was killed in a US raid in Syria in October, ISIS named its new 'caliph' as Abu Ibrahim al-Hashimi al-Qurashi, a jihadi alias not then known among counter-terrorism analysts. In its announcement the terrorist group provided no meaningful detail that might provide clues about his real identity.

After Baghdadi was killed and before ISIS named its new leader, CNN reported that some analysts believed al-Mawla would likely take over the leadership of the group.

The finding that ISIS is regenerating under a new leader challenges the narrative emanating from the White House. Earlier this month President Donald Trump stated, "Three months ago, after destroying 100% of ISIS and its territorial caliphate, we killed the savage leader of ISIS, al-Baghdadi, who was responsible for so much death, including the mass beheadings of Christians, Muslims and all who stood in his way."

But the UN findings parallel the assessment of senior US counter-terrorism officials. "No one thinks that just with the demise of the physical caliphate that Daesh is finished, " Jim Jeffrey, the US Special Representative for Syria and the Coalition to Defeat ISIS stated in a press conference last week, using an alternative name for ISIS. Jeffrey added that there were somewhere between 14,000-18,000 ISIS fighters "active between Syria and Iraq."

"They have shown in the past some reconstitution in Iraq, particularly in the area of Diyala and Kirkuk provinces. And to the south of the Euphrates, in areas where the Syrian regime should be responsible but largely is not, they've been quite active. So we are concerned," he stated.

The coalition's ability to maintain pressure on ISIS has been complicated by the fallout from the January 3 US drone strike at Baghdad international airport which killed the head of Iran's Revolutionary Guard Corps-Quds Force Commander Qassem Soleimani and a leading Tehran-backed Iraqi militia commander. In his news conference last week, Ambassador Jeffrey stated that "Coalition operations have been primarily on pause in Iraq as we focus on force protection." because of concern over potential reprisal attacks by pro-Tehran militias.

"Over time, obviously, there is a possibility of a degradation of the effort against Daesh if we're not able to do the things that we were doing so effectively up until a few weeks ago," Jeffrey added.

The UN report makes clear Trump's decision last autumn to draw down forces in Syria has created a greater risk of jail breaks by the thousands of ISIS fighters currently detained by Kurdish forces in northern Syria.

"The reduction of forces of the United States of America has raised concerns among Member States regarding the ability of security forces currently active in the north-east of the Syrian Arab Republic to maintain adequate control over a restive population of detained ISIL fighters, as well as family members."

The report estimated 10,000 male fighters remain in these facilities, including 2,000 foreign terrorist fighters and warns female detainees are playing a leading role in radicalizing those detained in the facilities. The report stated "the current improvised holding arrangement are a recipe for radicalization and despair, especially in the case of minors."

On October 22, during the tumultuous period which followed the Turkish incursion into Kurdish controlled areas of northern Syria and the US announcing it was drawing down troops in the area, Secretary of Defense Mark Esper told CNN , "Of the 11,000 or so detainees that were in prisons in northeast Syria, we've only had reports of a little bit more than a hundred that have escaped."

According to the UN report, the number of escapees ended up being higher. "Member States estimate that several hundred individuals associated with ISIL, including fighters, escaped from their accommodations in October, although it is not clear how many were redetained, how many remained at large and whether there was any significant change to the associated threat."

A genocidal Ideologue

If al-Mawla is one and the same as "al-Qurashi" and is the new leader of ISIS, he is likely to become one of the world's most wanted men. In August the US State Department's Rewards for Justice program offered a reward of up to $5 million for al-Mawla's capture, describing him as a "potential successor" to Baghdadi, while listing an alias as "Hajji Abdallah."

This assessment persisted after Baghdadi's demise. The day before ISIS announced their new leader in late October, Russell Travers, the acting director of the National Counterterrorism Center, testified that Hajji Abdallah was a potential successor.

The State Department listing further stated that Mawla/Hajji Abdallah, "was a religious scholar in ISIS's predecessor organization, al-Qa'ida in Iraq (AQI), and steadily rose through the ranks to assume a senior leadership role for ISIS. As one of ISIS's most senior ideologues, Hajji Abdallah helped drive and justify the abduction, slaughter, and trafficking of the Yazidi religious minority in northwest Iraq and is believed to oversee some of the group's global terrorist operations."

Much of the Yazidi community lived in Sinjar which is close to what some analysts believe was Mawla's hometown of Tal Afar in northern Iraq. In 2014, after ISIS had taken Tal Afar and Mosul, the group enslaved thousands of Yazidi women and children and murdered thousands of Yazidi men, in what the United Nations has called a genocide.

The 2019 "testimony" of a former ISIS operative which was archived by the researcher Aymenn al-Tamimi points to Mawla/Hajji Abdallah's involvement in ISIS's oppression of the Yazidis.

"The attack was carried out on the city of Sinjar and it was conquered ... and the Yezidis were brought together and it was said to them: 'All the men who convert to Islam will be spared from killing, and the women will spared from being taken captive' ... And the one who gave them the pact is al-Hajj Abdullah."

The former ISIS operative even included a footnote making clear "al-Hajj Abdullah" was Baghdadi's deputy. Tamimi also points to an internal ISIS document from 2018 in which a member of the group writes to Mawla about an ideological dispute. The letter (which for the record used the alias al-Hajj Abdullah) repeatedly described him as "the deputy" to Baghdadi.

As CNN has previously reported, there are suggestions Mawla is of Turkmen origin. If he is, that may have complicated his path to the top job. Iraqi Arabs have for the most part dominated ISIS's leadership ranks. There were also other hurdles Mawla faced. It is widely believed among jihadis that any "Caliph" must have certain credentials.

One is that he must be descended from the Prophet Mohammed's Quraysh tribe. Another is the requirement to have significant knowledge of Islamic jurisprudence. His track record as a "religious scholar" within the terrorist group may allow Mawla to persuade jihadis of his theological pedigree -- but it's unclear that he has Quraysh lineage.

According to the UN report, Mawla's "Turkmen ethnicity led some Member States to assess that he might only be a temporary choice until the group finds a more legitimate "emir," a direct descendant from the Quraysh Hashemite tribe who could therefore command the full support of the remote provinces."

This brings up the possibility that ISIS are deliberately keeping Mawla's elevation to the top position secret out of concern he may not be seen by jihadis around the world as a legitimate caliph.

But it is not clear how sustainable this will be for the terrorist group. Although pledges of allegiance have flowed into the new leader from fighters purporting to belong to ISIS satellites around the world, ISIS could risk losing support if they do not provide more biographical detail about their new leader.

"ISIL will face a challenge over the longer term to enthuse its supporters, especially those in more remote locations, about the new leader without putting him in danger by having him communicate more directly and confirm his identity," the UN report states.

Global threat picture

The picture the report paints of the global terror threat picture is that it has reduced overall since 2015-2017 when ISIS still controlled significant swaths of Syria and Iraq and launched and instigated a wave of attacks around the world. But there is also significant concern over the resilience of ISIS and its worldwide satellites, as well as the potential threat posed by the al-Qaeda network.

The report stated that "Al -Qaida affiliates are stronger than ISIL in many conflict zones, especially the Sahel, Somalia, Yemen and the north-west of the Syrian Arab Republic."

It warned that in West Africa, the combined efforts of al-Qaeda and ISIS affiliates "are threatening the stability of fragile Member States in the region."

The report stated that "ISIL appears not to have regenerated its external operational planning capability, although documents have emerged in the Syrian Arab Republic concerning a plan within ISIL to reconstitute its office to assist operatives in Europe with planning and executing attacks. Despite weaknesses in the current structure, the threat of a planned complex attack in Europe, especially by former expert operatives who have the ability to operate independently, is assessed to persist."

It reported that ISIS "suffered a setback to its ability to inspire attacks in November 2019, with the European Union Agency for Law Enforcement Cooperation (Europol) operation with several Internet companies that resulted in the removal of large quantities of ISIL online material, especially from Telegram's instant messaging platform."

In assessing the al-Qaeda threat, the report focused particular attention on Hurras al-Deen (HAD), a group of 3,500 to 5,000 al-Qaeda loyalists currently based in the Idlib province of Syria. "One Member State in the region assessed that HAD, given its size, ideology and the capabilities of its veterans, presented a growing threat to peace and security regionally and globally, and that its leadership plans to revive external operations targeting Western and United States interests wherever possible."

The report noted that "one Member State, however, highlighted Al-Qaida's conservative approach to expenditure and its consistent prioritization of administrative costs and salaries over operations. The ambitions of Al-Qaida affiliated elements in Idlib Province to plan and execute international attacks are assessed to be curtailed both by the military pressure they are under and by Al-Qaida's reluctance to resource such activity."

The report said that "Afghanistan continues to be the conflict zone of greatest concern to Member States outside the ISIL core area and suffers by some measures the heaviest toll from terrorism of any country in the world. Al-Qaida and foreign terrorist fighters aligned with it, under the protection and influence of the Taliban, pose a long -term global threat."

According to the UN relations between al-Qaeda (whose fighters are estimated between 400 and 600 in Afghanistan) and the Taliban "continue to be close and mutually beneficial, with Al-Qaida supplying resources and training in exchange for protection." The UN Monitors identified a pressing priority for al-Qaeda in Afghanistan: do everything possible to spoil a potential peace deal in the country. It noted that "Al-Qaida is concerned about the current focus of the Taliban leadership on peace talks. Al-Qaida representatives undertook shuttle diplomacy, persuading various factions of the Taliban and field commanders not to support negotiations with the Government of Afghanistan and promising to increase financial support."

The terrorist attack in the vicinity of London Bridge in November 2019 by a convicted terrorist the year after his release underlined the threat posed by the many terrorist convicts and radicalized inmates who are due to be released from European prisons in the coming years. According to the report, "many of the foreign terrorist fighters who received relatively short sentences upon their return to Europe prior to 2015 are expected to be released in the coming period. Some are still assessed to be dangerous. One member state reported that approximately 1,000 returnees were due for release in Europe in 2020."

The UN report warned that "the issue of foreign terrorist fighters remains acute, with Member States continuing to assess that between one half and two thirds of the more than 40,000 who joined the 'caliphate' are still alive. This is expected to aggravate the global threat posed by ISIL, and possibly Al-Qaida, for years to come."

It has long been clear that identifying and interdicting ISIS veterans should be a key priority for the international community. But the report warns that the "timely detection and identification of foreign terrorist fighters returning to Europe is complicated by their various travel routes and measures taken to avoid detection."