Police were forced to ram a van containing four BBC journalists after the driver allegedly failed to stop in County Donegal.
Some of those arrested are being held at Letterkenny Garda Station
It is understood the vehicle was not being driven by any of the journalists, who were investigating dissident republican activity.
Heavily armed police arrested seven people at the scene.
All of the journalists were released. Four other men arrested in a follow-up search are still being questioned.
The arrests were made under Section 30 of the Republic's Offences Against the State Act.
The BBC has said the journalists were working on a current affairs investigation and had full editorial authority under the BBC's guidelines.
A spokeswoman said the other people present were fully aware that they were with BBC journalists.
The men, aged between 30 and 48, who still are being held were taken into custody on Saturday night and Sunday afternoon.
'Forced to stop'
BBC Northern Ireland home affairs correspondent Vincent Kearney said members of the Garda emergency response unit stopped a van containing seven people.
"Four of those people were BBC journalists. The van, I understand, was not being driven by a member of BBC staff," he said.
"I am told that initially the driver of the van refused to stop when ordered to do so.
"The van was then forced to stop when it was rammed by a police car. Heavily armed police officers forced open the doors and arrested all seven men inside.
"They were taken to three separate police stations and questioned under section 30 of the offences against the state act - the Republic's anti-terrorist legislation.
"Shortly before midnight, the four BBC journalists were released without charge.
"Three others arrested with them are still being held, as are four other men who were arrested in a follow-up operation yesterday afternoon."
The men can be held for 72 hours, after which they have to be released or charged.