Comments made by the Irish Justice Minister comparing Sinn Fein to the Nazis have been rejected by Martin McGuinness.
Mr McDowell was speaking after comments made in newspaper
Michael McDowell claimed on Monday that some senior members of the party were members of the IRA army council.
Mr McDowell was speaking after comments made in a Sunday newspaper in which he likened Sinn Fein's relationship with the IRA to that of the Nazis and the Brownshirts.
Mr McGuinness said on Monday that Mr McDowell must "put up or shut up".
The Sinn Fein MP accused him of being "anti-working class" and "anti-republican".
"It's very well to make accusations but it is a whole other thing to substantiate those allegations," he said.
"I think Michael McDowell needs to remember that he is the Minister for Justice. He is not the Minister for Judges and he is certainly not the Minister for Juries."
Mr McGuinness said it was "electioneering by a desperate, ignorant and irrational politician".
In recent weeks, Mr McDowell has strongly criticised Sinn Fein over what he suggested are the party's double standards.
Mr McDowell said on Monday that Sinn Fein must choose between violence or democracy.
"They have a choice now, as to whether they embrace violence and paramilitarism, or make the final choice for democratic means alone," he said.
"You and I are not to be fairly expected to look at all those links and say they mean nothing.
"It's just like the Nazis and the Brownshirts - looking at them and saying they are two separate organisations and saying there's no connection - there's a very close connection."