Four arrested in connection with roadside mortar bomb discovery

Four men have been arrested after a mortar bomb, which gardaí say posed a significant threat, was found near Dundalk in Co Louth.

Gardaí found the explosive device after they stopped a car near the Dundalk exit on the M1 motorway shortly after 10pm last night.

The discovery was made by officers from the Special Detective Unit along with gardaí from the Louth Meath division, investigating the activities of dissident republicans.

The four men arrested, two in their 20s, two in their 30s, are being questioned at Drogheda, Balbriggan and Santry garda stations.

A team from the Army Disposal Unit spent more than four hours making the device safe at the scene last night.

"There was significant risk to the public," said Defence Forces Captain Pat O'Connor. "For that reason, a 5km stretch of road was closed off."