Letter bomb addressed to Northern Ireland Secretary Theresa Villiers is intercepted

Staff were evacuated and a stretch of Belfast's Limavady Road was sealed off as the area was made safe

A letter bomb addressed to Northern Ireland Secretary Theresa Villiers was discovered on Tuesday at the offices of the First Minister in Belfast. Bomb disposal experts arrived at Stormont Castle after the letter was found in the post room.

Staff were evacuated and a stretch of the city’s Limavady Road was sealed off as the area was made safe.

The discovery was the latest in  a sustained campaign. Letter and parcel bombs have been a tactic of republican and loyalist terror groups since the 1970s, but have seen a resurgence in recent months.

Two letter bombs were recently sent to the police, one in Londonderry and the other to the Chief Constable of Northern Ireland. Another was posted to the Public Prosecution Service in Londonderry. Dissident republicans were blamed in each of these cases.

Ms Villiers, who was in London on Tuesday meeting the former US diplomat Richard Haass, said she “utterly condemned” the attacks.

“If those responsible think that this kind of criminal activity will further any agenda, then they are completely mistaken.”

The Home Office has heightened the threat from extremists opposed to the peace process to “severe” in recent months. They have been responsible for the deaths of two soldiers, two police officers and a prison guard in recent years.

Northern Ireland’s First Minister, Peter Robinson, condemned the action. “Those responsible for sending this, and other devices, through the post have absolutely no regard for the lives of postal workers and staff working in offices,” he said. “They will not further any aim or objective by their vile and callous deeds. Northern Ireland will not be dragged back by terrorists who have nothing but misery to offer.”

Start your day with The Independent, sign up for daily news emails
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

Day In a Page

Aren’t you glad you didn’t say that? The worst wince-and-look-away quotes of the year

Aren’t you glad you didn’t say that?

The worst wince-and-look-away quotes of the year
Hollande's vanity project is on a high-speed track to the middle of nowhere

Vanity project on a high-speed track to nowhere

France’s TGV network has become mired in controversy
Sports Quiz of the Year

Sports Quiz of the Year

So, how closely were you paying attention during 2014?
Alexander Armstrong on insulting Mary Berry, his love of 'Bargain Hunt', and life as a llama farmer

Alexander Armstrong on insulting Mary Berry and his love of 'Bargain Hunt'

From Armstrong and Miller to Pointless
Sanchez helps Gunners hold on after Giroud's moment of madness

Sanchez helps Gunners hold on

Olivier Giroud's moment of madness nearly costs them
A Christmas without hope: Fears grow in Gaza that the conflict with Israel will soon reignite

Christmas without hope

Gaza fears grow that conflict with Israel will soon reignite
After 150 years, you can finally visit the grisliest museum in the country

The 'Black Museum'

After 150 years, you can finally visit Britain's grisliest museum
No ho-ho-hos with Nick Frost's badass Santa

No ho-ho-hos with Nick Frost's badass Santa

Doctor Who Christmas Special TV review
Chilly Christmas: Swimmers take festive dip for charity

Chilly Christmas

Swimmers dive into freezing British waters for charity
Veterans' hostel 'overwhelmed by kindness' for festive dinner

Homeless Veterans appeal

In 2010, Sgt Gary Jamieson stepped on an IED in Afghanistan and lost his legs and an arm. He reveals what, and who, helped him to make a remarkable recovery
Isis in Iraq: Yazidi girls killing themselves to escape rape and imprisonment by militants

'Jilan killed herself in the bathroom. She cut her wrists and hanged herself'

Yazidi girls killing themselves to escape rape and imprisonment
Ed Balls interview: 'If I think about the deficit when I'm playing the piano, it all goes wrong'

Ed Balls interview

'If I think about the deficit when I'm playing the piano, it all goes wrong'
He's behind you, dude!

US stars in UK panto

From David Hasselhoff to Jerry Hall
Grace Dent's Christmas Quiz: What are you – a festive curmudgeon or top of the tree?

Grace Dent's Christmas Quiz

What are you – a festive curmudgeon or top of the tree?
Nasa planning to build cloud cities in airships above Venus

Nasa planning to build cloud cities in airships above Venus

Planet’s surface is inhospitable to humans but 30 miles above it is almost perfect