A prominent Northern Ireland nationalist politician received three bullets through the post today.
The live rounds were delivered to the constituency office of SDLP South Down Assembly member PJ Bradley in Warrenpoint, Co Down.
It was the second time in two weeks that members of the party have been targeted - a viable letter bomb was sent to West Belfast Assembly colleague Alex Attwood last month.
Party leader Mr Mark Durkan said the latest threat was a "very serious development" which must be strongly condemned. He said those who were responsible, whether involved in the attack or in demonising SDLP members of the Policing Board and District Policing Partnerships must stop their activities.
"The pace of policing change has long ago justified the SDLP's decision on policing," he said. "The repeated attacks on our members will not hinder the SDLP driving the political and policing agenda.
"PJ Bradley's strong public stance for new policing and against old politics has made him, his staff and his family vulnerable," he said, pledging: "We will not be turned."
Meanwhile Sinn Fein also hit out at those responsible for an attack on the Belfast home of one of its councillors. Ball bearings smashed through the windows of the Poleglass home of Lisburn councillor Ms Veronica Willis.
Colleague Mr Paul Butler, a fellow councillor, said it was "only through good fortune" that no one was seriously injured.
He said it was the latest in a series of attacks and it was clear there was an "ongoing and orchestrated campaign of intimidation being carried out against Sinn Fein".