The men, held in the north of England under European arrest warrants yesterday, are accused of being part of an Islamist network that sent fighters to Iraq and Syria, discussed attacks on embassies in the Middle East and plotted to kidnap British and Norwegian diplomats, 'The Times' reported.
Eleven more alleged members were arrested in Finland, Norway and Italy yesterday but other suspects were said to have fled to Islamic State (ISIS) territory.
Giuseppe Governale, of the Special Operations Group, said that they had dismantled a cell with clear links to ISIS that also reached into Switzerland and Germany.
The four arrrested will appear at Westminster Magistrates' Court today to face extradition to Italy over international terrorism offences.
None of the arrested is a British national but Italian police said that the men were in the country legally.
Investigators accuse them of belonging to a group called Rawti Shax, which is described as a "terrorist organisation of Kurdish-Sunni origin".
