Image copyright Jeff J Mitchell Image caption Sinn Féin's Gerry Adams said the IRA had no part in the murder and had "left the stage" in 2005

Sinn Féin president Gerry Adams has said the IRA was not involved in the murder of ex-IRA man Kevin McGuigan Sr.

Mr McGuigan Sr died after he was shot at his home in east Belfast last week.

Mr Adams said the killing of the father-of-nine was carried out by "criminals who do not represent republicanism".

The BBC understands that police believe members of the Provisional IRA co-operated with a group called Action Against Drugs to carry out the murder.

Detectives believe it was in revenge for the killing of former IRA commander Gerard 'Jock' Davison in Belfast in May.

Threaten

Mr Adams said speculation that the IRA played a part in Mr McGuigan Sr's murder was wrong as the organisation had "left the stage" when it ordered an end to its armed campaign in 2005.

Mr Adams criticised those who he said had "opportunistically and cynically seized" on the murder to "undermine Sinn Féin's mandate and the peace process".

Image copyright PAcemaker Image caption Police believe Kevin McGuigan Sr's murder was in revenge for the killing of a former IRA commander

First Minister Peter Robinson had earlier said he would discuss the prospect of excluding Sinn Féin from the executive with other Northern Ireland parties.

Mr Adams said: "Those who threaten to take action against Sinn Féin in the assembly and executive have no basis whatsoever for this.

"Sinn Féin's mandate and the rights and entitlements of our electorate deserve exactly the same respect and protection as anyone else's."

Brutal

Mr Adams said Action Against Drugs was "a mix of criminals and former republicans who have engaged in intimidation and violence in pursuit of their criminal ends".

"The killing of Kevin McGuigan was wrong [and] my thoughts are with the McGuigan family." he added.

"Anyone with any information on this brutal murder should bring it forward to the Police Service of Northern Ireland.

"So, too, should anyone with information on the killing of 'Jock' Davison."

A 60-year-old man arrested on Friday in connection with Mr McGuigan Sr's murder was later released.