More than half the countries in the world are currently generating Islamist extremist fighters for groups such as al-Qaida and , the UN has said.
A report by the UN security council says there are more than 25,000 “foreign terrorist fighters” currently involved in jihadi conflicts and they are “travelling from more than 100 member states”.
The number of fighters may have increased by more than 70% worldwide in the past nine months or so, the report says, adding that they “pose an “immediate and long-term [terrorist] threat”.
The sudden rise, though possibly explained by better data, will raise concern about the apparently growing appeal of extremism. The geographic spread of states touched by the phenomenon has expanded, too.
The report notes continuing problems with understanding the processes of radicalisation, but says, despite a concentration on the internet, social networks in conflict zones and western cities play a key role.
“Those who eat together and bond together can bomb together,” the report says.
The report is the first from the UN to take a global view of the problem of “foreign terrorist fighters”, and includes those in , Africa and other theatres as well as Syria and Iraq.
Officials described the estimate of numbers as conservative and said the true total may be more than 30,000. “The rate of flow is higher than ever and mainly focused on movement into the Syrian Arab Republic and , with a growing problem also evident in Libya,” the report says.
The security council is meeting on Friday to discuss the problem of foreign terrorist fighters and potential measures to combat the threat.
The report comes amid a fierce debate over western strategies to counter Islamic State in and Iraq.
In recent days, Isis has made significant advances in both countries despite months of air strikes, leading to criticism of the US president, Barack Obama, and decision-makers in the region.
The US senator John McCain attacked the president on Sunday for citing climate change as a threat to national security, suggesting that the Obama administration’s focus on environmental issues was detracting from the fight against Isis.
Last week, the militant group seized the city of Ramadi, the capital of the predominantly Sunni Anbar province, its greatest victory in Iraq since its conquest of Mosul last summer and its declaration of a caliphate spanning swaths of Iraq and Syria.
The group also took control of the historic Syrian city of Palmyra and strategic gas fields nearby after a week-long siege that routed forces loyal to President Bashar al-Assad. The victory has triggered a humanitarian crisis, due to the flight of thousands of residents.
A series of public statements by senior officials in Washington and the Middle East have highlighted disagreements between the US, Iraq and Iran.
Earlier this year, General James Clapper, the director of US national intelligence, that officials now believed that 3,400 citizens from western nations, including 150 from the US, had travelled to Iraq and Syria to join violent militant groups.
More than 700 British extremists are thought to have travelled to Syria – with about half returning to the UK.
The new report describes Iraq, Syria and Libya as a “veritable finishing school” for terrorists and mentions Tunisia, Morocco, France and the Russian federation as particularly vulnerable to future attacks due to the number of fighters from there.
“Those that have returned or will return to their states of origin or to third countries may pose a continuing threat to national and international security,” the report said.
“Many may reintegrate, abandoning violence. Some have already gone on to organise further terrorist attacks and others will do so in the future.”
In May 2014, a French veteran of the conflict in Syria launched an attack on a Jewish museum in Belgium.
The killer of four people in a Jewish supermarket in Paris in January claimed to be from Islamic State though he was not a veteran of the conflict there. His wife had fled to Syria days before the attack.
Isis has repeatedly called on Muslims living in the west to mount “freelance” or “lone wolf” operations.
Alexander Evans, lead UN expert on al-Qaida and Isis, said there was a danger that the international community was becoming too focused on Syria, Iraq and Libya.
“The risk of people going and people returning is wider,” Evans said.
Afghan security forces estimated in March 2015 that about 6,500 foreign terrorist fighters were active in Afghanistan, the report notes. Most were from groups based in neighbouring Pakistan, though 200 were with the Islamic Movement of Uzbekistan and 150 with the Eastern Turkestan Islamic Movement which operates in south-west China.
There are fears of an upsurge in violence in Afghanistan as the US reduces its presence in the unstable state.
Volunteers have travelled to conflict zones where Islamic militants are active from countries including , and the .
“We have spent a lot of time worrying about the countries which have generated hundreds or even thousands of fighters but [there are] countries which may have never faced a terrorist threat of this nature and which have law enforcement and security authorities which are grappling with what is a new problem for them,” Evans said.