Evidence of three or more explosions has been discovered on the Dublin-Belfast railway line, the RUC has said.
The line has been closed between Dundalk, Co Louth and Portadown, Co Armagh since Saturday after explosions were heard near the border town of Newry in Co Down.
British army bomb disposal experts are at the scene of the explosion sites betwen Bessbrooke and Newry, a spokesman said. The rail line remains closed.
