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."

Shortly after telling the BBC his story the father, called Jahangir, received a call from Ashraf Ghani assuring him that arrests would be made.
His wife was allegedly raped in Badakhshan province eight years ago.
But Jahangir says he has been unable to get the alleged rapists arrested because they are politically powerful.
His wife told BBC Persian about the incident.
"I told one of them, for God's sake, I have just given birth, I'm like your child, even your daughter is older than me," she said.
"I cried a lot, they beat me all over my head and body," she said.
"Their bite marks were still on my body until a couple of years ago."
Analysis: Inayatulhaq Yasini, BBC Pashto
The stand taken by Jahangir and his wife breaks something of a taboo in Afghanistan, where victims of sexual crime are generally cowed into silence.
Soon after the media picked up the case, President Ghani spoke with Jahangir and promised him that "the case will be investigated properly and perpetrators will face justice".
The victim herself told the BBC: "I want justice to save other women from such a fate."
In the wake of the publicity, the Afghan government will be under pressure to investigate the incident properly and ensure some kind of resolution.
But there are also hopes that the stand taken by Jahangir and his wife will embolden other victims of sexual crime, and have a lasting affect on how such cases are dealt with.
Jahangir, a policeman, told the BBC eight men were arrested after the incident, but six have now been freed because of their political connections.
He says he and his family had to flee to the capital, Kabul, fearing for their lives.
He has threatened to kill himself unless that changes: "If they are not put on trial, I'll have to commit suicide to escape the tensions I'm suffering from. There's no other way."
Jahangir went public with the threat on Afghan television. He later met the country's interior ministry to press his case.
While speaking to the BBC following the meeting, he received a phone call from Mr Ghani. He wept as they spoke.
Mr Ghani was sworn in as Afghan president in September, pledging to tackle the issue of corruption as a priority.
As well as political corruption, activists say violence against women is rife in Afghanistan, but rarely attracts much public attention.
In one case that did spark national outrage, five Afghan men convicted of gang raping four women were hanged in October.
Four men have been arrested in the UK following a counter-terrorism operation led by Italian authorities, the North East Counter Terrorism Unit says.
[NEXT_CONCEPT]
The president of Afghanistan has told an emotional husband that a group of men accused of gang raping his wife would be brought to justice.