Gerry Adams talked about "damage" to the political process
Sinn Fein President Gerry Adams has said he believes the political process is in "deep crisis".
He was speaking after he led a party delegation to meet the prime minister in London to discuss the fallout from a report into paramilitary violence.
Friday's meeting came days after Northern Ireland Secretary Paul Murphy's announcement that financial sanctions would be imposed on Sinn Fein and the Progressive Unionist Party.
Both parties have vowed to challenge the move, which came after the Independent Monitoring Commission highlighted the levels of paramilitary activity by both republican and loyalist groups.
Mr Adams said: "We told the prime minister that we totally and absolutely reject and resent the effort by the two governments to penalise and discriminate against our party through the IMC report.
"I have to say that there is a fundamental difference of opinion between Mr Blair and Sinn Fein on this issue."
Mr Adams said a period of intense talks was needed to get the political process back on track.
Tony Blair met members of Sinn Fein
He said that Mr Blair was pressed over the issue of collusion, with particular regard to the murder of Belfast solicitor Pat Finucane in 1989.
"We said that the rejection of the Finucane family's request for an independent judicial inquiry is totally unacceptable," he added.
Mr Adams said while Sinn Fein remained committed to the process, "others have to keep both their focus and commitments".
Sinn Fein is expected to meet Irish Prime Minister Bertie Ahern in Dublin next week.
Meanwhile, a review of the Good Friday Agreement is due to begin again on Tuesday.
Paul Murphy confirmed the date after he held talks with Irish Foreign Minister Brian Cowen at a session of the British-Irish Intergovernmental Conference on Wednesday.
Mr Murphy said the governments would be writing to all the political parties in the next few days and hoped they would all take part in the review.
However, the Ulster Unionist Party has said it is going to talk to the government before deciding whether to take part in the talks.
The party walked out of the review in February over Sinn Fein's continuing participation in the talks amid alleged IRA activity.
A party spokesman said they wanted to find out about the nature of the review before deciding if they will attend.
SDLP leader Mark Durkan met Mr Blair at Downing Street on Wednesday and described the talks as "good".
Mr Durkan said financial sanctions resulting from the IMC report would not impact on those they were designed to, or impress those they were supposed to impress.
The latest crisis in the political process was triggered by the alleged abduction of dissident republican Bobby Tohill in February, which Chief Constable Hugh Orde immediately blamed on the IRA.
The four-man commission is a crucial element in the two governments' plans for restoring devolution, which was suspended in October 2002 amid allegations of IRA intelligence gathering at Stormont.