New evidence presented by experts to the United Nations Security Council has found that Isis is still a dangerous and capable militant organisation, despite its recent heavy losses across its territory in Syria and Iraq.

The 24-page report, discussed by member nations on Thursday, found there is ongoing Isis resistance in Mosul, despite the fact the Iraqi city was declared liberated by US-backed Iraqi coalition forces in July.

The bitter fight put up by militants showed that Isis’ command and control structure “has not broken down completely”, and remains “a significant military threat” by delegating decision-making responsibility to local commanders and switching to encrypted communications.

Footage shows Isis schoolgirl Linda Wenzel being captured in Iraq

The organisation has also become skilled at modifying or building its own drones for both spying and bombing purposes, it said.

While the group’s financial situation is becoming more precarious, Isis is still raking in funds from oil profits, taxing and robbing local populations under its control and small inconspicuous remittances from supporters abroad, the report found, allowing it to “motivate and enable” international terror attack efforts.

Foreign fighters returning to their countries of origin as the caliphate crumbles pose a particular threat, the experts said, and radicalised children and teenagers in particular require “specific attention and strategies that take into account the legal protections afforded to minors”.

Outside Syria and Iraq, it is likely the top levels of the organisation will attempt to expand its operations in south-east Asian countries such as the Philippines, which is currently battling a bloody Isis insurgence that has killed 700 people in the city of Marawi.

In pictures: Isis' weapons factories Show all 11 1 /11 In pictures: Isis' weapons factories In pictures: Isis' weapons factories A mortar round fin manufactured by Isis in Gogjali, Mosul, November 2016 Conflict Armament Research In pictures: Isis' weapons factories Isis rocket components discovered in Gogjali, Mosul, Iraq in November 2016 Conflict Armament Research In pictures: Isis' weapons factories Isis mortars discovered near Karamlais, Iraq, in November 2016 CAR In pictures: Isis' weapons factories An Isis rocket launch frame in Qaraqosh, November 2016 Conflict Armament Research In pictures: Isis' weapons factories A memo from Isis' COSQC on quality control at a manufacturing facility in Gogjali, Mosul, November 2016 Conflict Armament Research In pictures: Isis' weapons factories Electrically-operated initiators manufactured by Isis in forces Gogjali, Mosul, November 2016 Conflict Armament Research In pictures: Isis' weapons factories Isis mortar tubes at a manufacturing facility in Karamlais, November 2016 Conflict Armament Research In pictures: Isis' weapons factories An Isis mortar production facility discovered in Gogjali, Mosul, in November 2016 Conflict Armament Research In pictures: Isis' weapons factories An Isis weapons manufacturing facilities near Mosul in November 2016 Conflict Armament Research In pictures: Isis' weapons factories Stocks of French-manufactured Sorbitol, Latvian potassium nitrate and Lebanese sugar at an Isis weapons factory in Iraq Conflict Armament Research In pictures: Isis' weapons factories A destroyed Isis weapons facility in Qaraqosh, Iraq, November 2016 Conflict Armament Research

Isis leaders have also sent money to places where the group doesn’t have affiliates in an attempt to prepare for its eventual defeat in Iraq and Syria, according to an unidentified UN member state quoted in the report.

Isis and al-Qaeda both still pose a significant threat in and from Yemen, the authors said, where more than 30 recent failed extremist plots targeting areas in the Middle East originated from the war-torn country.

Al-Qaeda’s networks in the Arabian Peninsula, East and West Africa remain strong, the report said.