A 34-year-old man, arrested for quesioning in connection with the Omagh bombing in August 1998, has been charged with a number of terrorist offences.
He is due to appear at Craigavon Magistrate's Court tomorrow morning, charged with a series of offences including possessing explosive substances with intent to endanger life and membership of a proscribed organisation.
The PSNI has refused to confirm reports that he has been charged with conspiracy to cause the Omagh bomb.
He was arrested in Jonesborough, south Armagh on Tuesday morning during an operation involving up to 200 police officers and troops.
His wife, who was arrested at the same time, was released without charge yesterday.
The man has been questioned before by police about the bombing - the single worst atrocity in the 30-year history of terrorist violence in Northern Ireland.
He is being held in Gough Barracks in Armagh city, and was also being questioned about a series of other attacks carried out by dissident republicans.
These include bombings in Lisburn, Co Antrim, and Newry and Banbridge, Co Down, which came before the Omagh attack in which 29 people were killed, including the mother of unborn twins, and more than 200 others were injured.
Only one person has been convicted in connection with the bombing - publican Colm Murphy, who received 14 years in the Special Criminal Court in Dublin for helping to plot the attack.
Last month, Michael McKevitt was also convicted of directing terrorism.
However, he was convicted directly of involvement in the Omagh bombing.
A civil action has been launched by some of the relatives of those killed in Omagh against five dissident republicans, who they believe were responsible for the bombing.
McKevitt and Murphy were among the five people named on writs for the civil action.