A suspicious package found at a postal sorting office is believed to be linked to the parcel bomb sent to a Scottish university, Ireland's justice minister has said.

The package, which was discovered in Limerick on Friday morning, had a similar stamp to a letter bomb sent to the University of Glasgow earlier this month.

A group calling itself the IRA claimed responsibility for the device, as well as for letter bombs sent to major transport hubs in London.

Read more: University of Glasgow: Bomb disposal experts carry out controlled explosion

The group claimed it posted five devices to addresses in Britain, but only four had been discovered at the time the claim of responsibility was sent to a Belfast newsroom.

The organisation, known to police as the New IRA, claimed one parcel, addressed to a British army recruitment officer, may not have been discovered yet.

Justice Minister Charlie Flanagan told RTE: "This is a despicable act.

"The sending of incendiary devices like this is totally unacceptable. I hope the people responsible are brought to justice."

Mr Flanagan said the item found in Limerick could be the fifth device.

He added: "We have reason to believe this could be the case." 

A Garda spokesman said: "Shortly after 6am, Gardai in Henry Street received a report of a suspect package at the An Post sorting office, Dock Road, Co Limerick.

"The building has been evacuated and the army EOD team have been notified."