An alleged terror plot linked to Islamic State is identified in the West every fortnight, a report suggests.
Between July last year and August this year, 32 suspected plans were detected in 10 countries, an average of more than two a month, according to research by think-tank the Henry Jackson Society.
They involved 58 individuals of 14 nationalities, with 13 attacks taking place, the study said.
Researchers said that in three-quarters of cases there was no proof of contact with IS fighters or leaders, but added that the group's ideology or propaganda was "integral" to inspiring the schemes.
On five occasions IS militants were said to have encouraged individuals to carry out attacks in their home countries without providing "operational guidance".
Only one plot was directed by the terrorist group, also known as Isil, the report said.
Lead author Robin Simcox said: "The Islamic State presents a clear danger to Western security. Over-stretched police and security services are struggling to keep up with the vast scale of the threat."
The report also said:
:: The US was targeted in the highest number of alleged plots, with 12, followed by Australia and France
:: Guns were the most commonly used weapons
:: The internet was "relevant" in 27 of the 32 plots, with material accessed online said to have inspired or played a role in radicalisation in almost half of cases
:: Nearly all (97%) of those accused of being involved in the plans were men, three-quarters were under 25 and nearly one in three (29%) was a convert to Islam
Mr Simcox said: "Those carrying out plots associated with the Islamic State are often radicalised young men who very rarely had any military training.
"They have been effective in planning simple attacks using guns and knives to target members of the public, the military and the police. Such plots are notoriously difficult to prevent."