Political progress in Northern Ireland will be stalled until Sinn Féin deals with IRA criminality, the Northern Ireland secretary, Paul Murphy, said today.
The minister, speaking from Washington, said the ball was firmly in the court of republicans to deal with the issue once and for all.
"To all intents and purposes we are not talking about any future negotiations or discussions until the issue of criminal activity on the part of the IRA is addressed," he told the BBC. "The onus is entirely on the leadership now of Sinn Féin to resolve the issue of criminality, and until that happens we have not got any hope at all of making any progress towards restoring the institutions of government in Northern Ireland."
Mr Murphy said the visit of the McCartney sisters to the US capital over the St Patrick's Day holiday had brought IRA violence and thuggery into sharp focus.
"The fact that they have got this remarkable campaign has personalised the issue of criminal activity in a way which, here in the US, has been very well understood because people see individual human beings being affected by brutality and savagery."
The McCartney family travelled to Washington to highlight their campaign for the murderers of their brother Robert to be brought to justice. The five sisters and Mr McCartney's fiancee, Bridgeen Hagans, have met President George Bush and other leading US politicians, while Sinn Féin president Gerry Adams has been snubbed by the political establishment in the US capital.
Mr Murphy said the reaction of Irish Americans could have a positive impact on the family's campaign back in Northern Ireland, encouraging witnesses to come forward and give evidence.
"I hope that people who have any knowledge at all of that murder can feel satisfied in the sense that everybody across the world would be behind them if they come forward with information."
Earlier, Mark Durkan, the SDLP leader, said the unwavering stand of the five sisters had moved the peace process at unprecedented speed.
"The McCartney family is very clear about what justice demands and has held strong to those demands where the two governments have faltered," he said. "By doing that they have moved the movement on five times in as many days."
Mr Durkan said the McCartney sisters' determination to accept nothing but the truth had spurred leading politicians.
"Although it was not their intention, the McCartney family has sent out a clear message to the two governments about how to deal with the Provisional movement," he said. "Vague statements will no longer be enough."
Mr Durkan, who travelled to Washington for St Patrick's Day despite the White House snub issued to all Northern Ireland political leaders, said it would now be difficult for the government and Sinn Féin to hide such criminal activity.
"There needs to be a clear and complete wind-up of the IRA, no fudge, nor more terminology about sequencing, just direct action," he said. "The McCartneys have made this case in a very direct way, and it raises contradictions that the process cannot afford to carry."
The McCartneys said Mr Bush's detailed knowledge of their campaign had heartened them and given them hope. As their whirlwind tour of Washington drew to a close, they said the president's unconditional support had encouraged them to take their fight for justice as far afield as possible.