North reaction: Republicans and Sinn Féin dismissed the IMC report's findings and accused its authors of political bias. However the Rev Ian Paisley claimed the report vindicated the DUP stance on not entering talks with Sinn Féin.
Martin McGuinness said the report was "the work of an anti-republican body which is little more than a proxy for 'securocrats' and political detectives".
Sinn Féin's chief negotiator added that it had "no place in the political process" as it "subverts the democratic mandate of all the political parties, specifically Sinn Féin". The four members of the commission were "hostile to Irish republicanism".
The Provisional IRA unexpectedly issued a statement denying it had failed to meet its commitments to a purely political path.
A statement, signed by P O'Neill, claimed: "Recent allegations that the IRA is in breach of its public commitments are false. The IRA has honoured all commitments made on the 28th July 2005." Allegations to the contrary are "politically motivated".
However, Dr Paisley said the report "reaffirms what we already know - that the Provisional IRA is riddled with illegality".
Speaking at Westminster, he said: "In terms of rioting, intelligence-gathering, assaults, exiling and large-scale criminality, Sinn Féin/IRA has not turned its back on violence and criminality but is instead as actively involved in illegality as it has ever been."
He said the report "dispels the nonsense suggested by the [ British] government that ongoing IRA terrorism and criminality are the deeds of individuals acting without the say-so of the Sinn Féin/IRA leadership.
"It is particularly perturbing that the IRA continues its intelligence-gathering operation and is predominantly directing its spying at furthering its political strategy. The continuing targeting of 'public and other institutions' as outlined in the IMC report surely sends a message to the government that the reinstating of Sinn Féin allowances is both premature and pure folly."
Dr Paisley said it was of "grave concern" to the DUP that the report stated "not all PIRA's weapons and ammunition were handed over for decommissioning".
Sir Reg Empey accused republicans of still being wedded to a "failed ideology whose time has passed". The Ulster Unionist leader called on Gerry Adams to explain the republican movement's action in light of the report's findings. "They cannot let go of crime or covert intelligence-gathering. When coupled with news of raids in the Republic linked to IRA money-laundering, it is clear that they still have some way to go towards exclusively peaceful and democratic means." He also asked for clarification on the retention of IRA weapons, and stressed that an "immediate return to the Executive is just not on the political radar".
SDLP leader Mark Durkan said it was important for unionists to take note of how far republicans had come and not simply to dwell on what remained outstanding.
His party's justice spokesman Alban Maginness said the report also "vindicates the SDLP'S concern that some restorative justice schemes are really about keeping paramilitary control of nationalist areas".
For the Alliance party, David Ford urged people to judge the IMC report on its contents. "It would have been better for the [ British] government to say nothing [on the report] and let the facts speak for themselves. Any appearance of spin only aids those unionist refuseniks who are searching for any excuse to not engage."
The Rev Harold Good, one of the independent witnesses to the decommissioning of IRA weapons, voiced his concern at the report's findings. "However we do it, we must remove all doubts about weaponry and the existence of people who are continuing, if that is true, to hold on to anything. I want to repeat what I said in September about what I saw: vast amounts of weaponry, armaments and explosives being put totally and permanently beyond access and beyond use. That I stand over. In the light of all of that, I cannot see how the IRA could actually continue an armed campaign without having to go through the process of rearming somewhere."