Six people have been arrested on suspicion of dissident republican terrorist activity, the Police Service of Northern Ireland has said.
The five men and one woman are being questioned by detectives from the serious crime unit in Antrim.
Three of the men were arrested in west Belfast last night and two in Derriaghey, while the woman was arrested in Dunmurry.
Last month Assistant Chief Constable Alistair Finlay insisted that the PSNI is prepared for any upsurge in terrorist activity ahead of this summer's G8 conference.
The senior officer said he was aware that anti-capitalist militants could align themselves with dissident republicans to disrupt the meeting in Co Fermanagh in June.
"Dissident republican activity is sadly an ongoing feature of Northern Ireland," he said.