A report by the United Nations, obtained by the Guardian newspaper, reveals that foreign jihadist fighters are flocking to battlefields in Iraq and Syria on an “unprecedented scale” since the United States and other allies began a wave of military operations in those countries over the last several months.

According to the Guardian’s Spencer Ackermann, the UN report

finds that 15,000 people have travelled to Syria and Iraq to fight alongside the Islamic State (Isis) and similar extremist groups. They come from more than 80 countries, the report states, “including a tail of countries that have not previously faced challenges relating to al-Qaida”.

The UN said it was uncertain whether al-Qaida would benefit from the surge. Ayman al-Zawahiri, the leader of al-Qaida who booted Isis out of his organisation, “appears to be maneuvering for relevance”, the report says.