The unit was assisted by officers from Humberside, Derbyshire, South Yorkshire and the West Midlands.
The arrests are part of a pre-planned operation relating to alleged terrorism offences under Italian legislation.
Police said the four men will appear before Westminster Magistrates Court but did not specify a date.
The arrests took place under European Arrest Warrants, police added. Those arrested face extradition to Italy.
Jihadist cell in Europe 'sought recruits for Iraq and Syria'
The men were part of raids in several European countries connected to a suspected "jihadist network" which was allegedly plotting to free its leader, Mullah Krekar, who is in detention in Norway.
Six suspects were detained in Italy and three in Norway. Krekar was among those arrested.
Italian police said the group was planning to seize Norwegian and British diplomats to try to secure Krekar's release.
Italy's Ansa news agency said the suspects were being accused of international terrorism association.
The men arrested in Britain are:
The terrorism unit said the men are being held at a police station in the north of England and will not be questioned by officers in the UK.
The addresses of the men are being searched, and after appearing before magistrates they will be handed over to Italian authorities.
A statement from the North East Counter Terrorism Unit said: "We understand that people may be concerned following today's arrests.
"However, we would like to reassure communities that today's activity is as a result of an ongoing investigation which is intelligence led.
"There is no evidence to suggest that communities are at risk."
Four men have been arrested in the UK following a counter-terrorism operation led by Italian authorities, the North East Counter Terrorism Unit says.