The presidents of the European Commission and the European Parliament gave their backing Wednesday to the campaign by sisters of a murdered Catholic man to bring his killers to justice.

Robert McCartney, a 33-year-old father of two, was stabbed and beaten to death in a Belfast street in January following a row in a bar before more than 70 witnesses.

McCartney's sisters and fiancee have alleged that the Irish Republican Army paramilitary organisation has intimidated witnesses against testifying about a murder that even the IRA has admitted involved at least two of its members.

"On behalf of the European Parliament, I wish to express my full support to the campaign of the McCartney's sisters", President Josep Borrell said after meeting with three of them, Catherine, Paula and Gemma.

"The doors of the European Parliament will always be open to those who need a public tribute to fight any kind of injustice," he added.

He promised to bring up the plight of the sisters with the heads of the parliamentary groups on Thursday in order "to break the 'wall of silence' surrounding Robert's murder".

Commission president Jose Manuel Barroso said: "It is not for the Commission to interfere with the judicial enquiries and legal procedures of a member state, but the courage, dignity and quest for truth and for justice which the McCartney family embodies deserves to succeed."

McCartney's family has already taken their campaign last month to the United States, where they won support from US President George W. Bush.