Chris Lyttle MLA said: “This is an attack on democracy. Theresa Villiers is a democratically elected Member of Parliament and holds a key position within the Government, while those responsible for this device have very little support and whose only aim is to cause violence and disruption across Northern Ireland.
“There is no place in our society for the reckless actions of those behind this letter bomb. Somebody could have been killed or seriously injured had this device exploded.
“It is deeply worrying that this is the fourth letter bomb to have been sent in the past week. I would like to praise the work of the police, army and postal staff who have dealt with these devices.
“If anybody has any information about this letter bomb then I would urge them to contact the police.”