Belfast, Northern Ireland (CNN) -- Three men arrested over dissident republican activity in Northern Ireland appeared in court Thursday and were remanded into custody, police said.
The men, all in their 20s, are accused of possessing a firearm with intent to endanger life and possession of ammunition in suspicious circumstances.
They were arrested Monday night when police officers stopped and searched a car in Cookstown, County Tyrone. Police said they found a gun and ammunition during the search.
The accused are Mark McGuigan, 26, from Omagh, and Martin McClune and Darren Patrick McCallion, both 22 and from Londonderry.
A detective from the Police Service of Northern Ireland (PSNI) told Strabane Magistrates Court on Thursday he believed the men were conducting operational activity with the Real IRA, a dissident republican group.
A fourth man arrested at the same time is already in custody, the PSNI said.
The Irish Republican Army, also called the IRA, fought a bloody campaign against British rule in Northern Ireland for decades before starting a process of decommissioning nine years ago.
Those who refused to accept the Good Friday Agreement that led to the decommissioning are known as dissident republicans, and they include an IRA splinter group known as the Real IRA.