Two men have been arrested in Belfast in connection with the investigation into a van bomb left near Newry last April.
The 250kg device was left on the outskirts of the town on the A1 road near the main Dublin-Belfast railway line.
It led to a protracted security alert.
A PSNI spokesman said two men, aged 35 and 36, were arrested in Belfast city centre this morning.
They are being held at Antrim police station for questioning.
