More than 20,000 foreign fighters have fled to Syria and Iraq, turning the region into an ‘international finishing school’ for jihadists, an alarming report found. Fighters from 100 nations – more than half the countries in the world – have joined militant groups such as Al Qaeda and Islamic State, according to research by the United Nations. Worryingly, the report warned if IS was defeated in the war-torn region then the barbarous foreign fighters could be scattered across the world. Scroll down for video . More than 20,000 foreign fighters from more than half the countries in the world have joined militant groups such as Al Qaeda and Islamic State, according to a report by the United Nations . The number of foreign fighters worldwide soared by a staggering 71 per cent between the middle of 2014 and March 2015 after IS gained significant territory. Syria and Iraq were by far the biggest destinations, with over 20,000 foreign fighters travelling to the region to fight for mainly IS but also the Al-Nusra Front. The panel said the thousands of foreign fighters who travelled to both countries are living and working in ‘a veritable “international finishing school” for extremists’ as was the case in Afghanistan in the 1990s. Afghan security forces estimated in March – three months after British troops withdrew - that about 6,500 foreign fighters were active in the country. And it said hundreds of foreigners are fighting in Yemen, Libya and Pakistan, around 100 in Somalia, and others in the Sahel countries in northern Africa, and in the Philippines. The panel of experts monitoring UN sanctions against Al-Qaeda said in the report that the scale of the problem has increased over the past three years and the flow of foreign fighters ‘is higher than it has ever been historically’. The number of foreign fighters worldwide soared by a staggering 71 per cent between the middle of 2014 and March 2015 after IS gained significant territory . The overall number of foreign terrorist fighters has ‘risen sharply from a few thousand ... a decade ago to more than 25,000 today,’ the panel said in the report to the UN Security Council. A military defeat of the Islamic State group in Syria and Iraq could have the unintended consequence of scattering foreign terrorist fighters across the world, the panel said. It noted that the ‘watch list’ in Turkey - a key crossing point to Syria and Iraq - now includes 12,500 individuals. And while governments are focusing on countering the threat from fighters returning home, the panel said it’s possible that some may be traumatised by what they saw and need psychological help. Others may be recruited by criminal networks. The number of countries the fighters come from has also risen dramatically from a small group in the 1990s to over 100 today, including some that have never had previous links with Al-Qaeda associated groups, the panel said. It cited the ‘high number’of foreign fighters from Tunisia, Morocco, France and Russia, the increase in fighters from the Maldives, Finland and Trinidad and Tobago, and the first fighters from some countries in sub-Saharan Africa. Syria and Iraq were by far the biggest destinations, with fighters mainly travelling to the region to fight for  IS but also the Al-Nusra Front (pictured, a fighter from the Al-Qaeda linked militant group) The panel said the fighters and their networks ‘pose an immediate and long-term threat’ and ‘an urgent global security problem’ that needs to be tackled on many fronts and has no easy solution. With globalised travel, it said, the chance of a person from any country becoming a victim of a foreign terrorist attack ‘is growing, particularly with attacks targeting hotels, public spaces and venues’. But the panel noted that a longstanding terrorist goal is ‘generating public panic’ and stressed that the response needs to ‘be measured, effective and proportionate.’ It said the most effective policy is to prevent the radicalization, recruitment and travel of would-be fighters. The panel noted that less than 10 per cent of basic information to identify foreign fighters has been put in global systems and called for greater intelligence sharing.
Number of foreign fighters worldwide soared by 71% from mid-2014 to now .
Syria and Iraq were most popular regions - mainly for IS and Al-Nusra Front .
United Nations report said fighters came from over half world's countries .
It warned if IS was defeated foreign fighters could scatter across the globe .