British Prime Minister David Cameron has described a Real IRA rally in Derry as "unacceptable".
A masked member of the terror group read out a statement at Creggan cemetery on Easter Monday, threatening to kill more police officers.
Mr Cameron was today asked about the event during question time in the House of Commons.
He said the PSNI is being backed with the right amount of money and urged officers to track down those responsible.
"Above all the words that should ring in our ears are those of the mother of police constable Ronan Kerr, who said that she hoped that this would not stop more Roman Catholics joining the PSNI and doing a great job policing Northern Ireland," Mr Cameron said.