Taoiseach's reaction: The findings of the Independent Monitoring Commission's investigation into paramilitary activity are "disturbing and worrying", the Taoiseach, Mr Ahern, has said.
However, he said the conclusions offered by the IMC after months of inquiry could not deflect from efforts to get the Northern political institutions back up and running.
Refusing to rule out negotiations with any of the parties, including Sinn Féin, Mr Ahern said: "I have to continue to deal with all of the parties. If I don't do that I will not make progress."
Speaking in Swords, Mr Ahern said: "It is unacceptable to me that there is any link between politics and paramilitary activity. I have said that time and time again."
However, he rejected Sinn Féin's charges that the IMC is not independent. "We accept its recommendations. We accept its conclusions."
The findings backed up criticism levelled by the Government against the IRA, even though Sinn Féin had argued that the Government was "exaggerating it for some political reason", he said.
The IMC was "saying that these facts are not only true, but that there is a disturbing level of activity, that there is a disturbing level of criminality, that there is a link between political parties and paramilitaries. They are saying all of these things very bluntly in the report.
"This report shows that paramilitarism and criminality has been thriving away in the background while those of us in the political process have been trying to make progress," he said.
The commission had reported quickly, he noted. "Some people were trying to say that we were trying to miss the summer. Others said that we would play it into election time in the summer.
"We have done neither. The IMC brought it forward three months early. I think that that is a very good thing."
If they had been in place, the Northern Ireland Assembly and the Executive would have been thrown into crisis because of the report's findings. "If the institutions were up and running now they would obviously be going for far harder measures than they are, up to exclusion. That would put us right back. Time and time again, I have said collectively we need to find a mechanism to move forward. That has to include the separation and segregation of paramilitary activity. Otherwise we cannot do it."
Asked if Sinn Féin was "fit" for government, the Taoiseach said: "My position is that I don't see too much in this report that I did not actually feel, as you know.
"Sometimes when we say it there is thought to be some other motive. I just want to see the end of paramilitarism."
Reacting to the report, the Minister for Justice, Mr McDowell, has said it backs up his previous claims about Sinn Féin members holding senior positions in the IRA and their involvement in organised criminal activity.
He said the important aspects of the report were the conclusions that some senior members of Sinn Féin held senior positions in the IRA, that the IRA was still carrying out punishment beatings, and that it was financed by crime.