A bullet intercepted in the post was addressed to the home of Sinn Féin president Gerry Adams, the party revealed today.
The 'letter' was one of 12 envelopes containing bullets addressed to Sinn Féin representatives in the North, which were intercepted at Northern Ireland's central sorting office on Wednesday.
The packages are still undergoing scientific examination by police.
Sinn Féin MLA Mr Conor Murphy said along with yesterday's attack on a Belfast bar by loyalist paramilitaries, showed a violent campaign was being stepped up.
The Red Hand Defenders - a cover for the UDA - has admitted responsibility for the attack.
"Unionist politicians will no doubt continue to focus their attentions on the silent guns of the IRA while ignoring and, in some cases, justifying ongoing unionist paramilitary attacks on the nationalist community," Mr Murphy said.
He also revealed one bullet made it through postal system and was delivered to the home of west Belfast councillor Mr Paul Maskey.