A parcel bomb found at a postal depot in Ireland has been linked to a suspicious item sent to Glasgow University earlier this month.

The "viable improvised explosive device" contained in a plastic envelope, was found in Limerick on Friday and appears identical to items sent to London and Glasgow on March 5 and 6.

Police investigating the suspicious packages sent to the UK have said a claim of responsibility has allegedly been made on behalf of a group called the "New IRA".

Officers say that the package found in Limerick could have been returned there having never reached its intended target in London.

The Metropolitan Police and Police Scotland are now working closely with their counterparts in Ireland.

Deputy Assistant Commissioner Dean Haydon, Senior National Co-ordinator for Counter Terrorism Policing said: "Whilst it is still early, from the images we've seen and from speaking to our counterparts in the Republic of Ireland, it appears that the package found in Limerick is linked to those sent to London and Glasgow on 5 and 6 March.

"One line of enquiry is that the package found today in Limerick was returned there having never reached the intended recipient in London.

"We will continue to work closely with our counterparts at both An Garda Siochana and Police Scotland to identify those responsible for sending these packages and enquiries are very much ongoing.

"We are also aware that a claim of responsibility made on March 11 referenced there being a fifth package. Whilst that remains a line of enquiry, we continue to keep an open mind on who may be responsible and any potential motivation.

"I must also stress that we continue to urge the public to remain vigilant for any suspicious packages and to report anything suspicious to police."

Army bomb disposal experts were called to the postal sorting office in Limerick after the suspicious package was discovered on Friday morning.

Irish Justice Minister Charlie Flanagan said a stamp on the package found in the An Post depot on Dock Road in the city was similar to those used on letter bombs sent to the UK earlier this month.

He added: "This is a despicable act.

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

The building was evacuated during the security alert.

A spokesman for the Defence Forces said: "A viable improvised explosive device contained in a plastic envelope was identified and made safe. The device was then handed over to An Garda Siochana for further investigation."

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

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

The packages that arrived at Waterloo railway station and offices at Heathrow and London City airports on March 5 and 6 were posted with Irish stamps and had Dublin as the return address, prompting Irish police to join the investigation.