But some lawmakers here said they were concerned and disturbed by the new revelations. Democrats, both in Springfield, Ill., and Washington, said they were trying to digest the details of Mr. Burris’s disclosure and would withhold further comment.

Some Republicans said they believed local prosecutors should pursue a perjury investigation against Mr. Burris, and some suggested that his disclosures might actually have been prompted by concerns that some of his conversations with Mr. Blagojevich’s allies were recorded by federal authorities during the corruption investigation that led to the former governor’s political downfall.

“I can’t believe anything that comes out of Roland Burris’s mouth anymore,” said Jim Durkin, a Republican state representative who served on the impeachment committee and posed the original line of questioning. “I just don’t know how to reconcile this. I don’t accept that this is a lapse in memory. How would you forget talking to the governor’s brother? This is the third variation of him describing his relationship with the governor and the circumstances of his appointment.”

Mr. Burris’s description of his contacts with Mr. Blagojevich’s allies has repeatedly evolved.

On Jan. 5, Mr. Burris voluntarily submitted a sworn affidavit to state lawmakers saying that before he was selected for the Senate seat days earlier “there was not any contact” between himself or his representatives and those of Mr. Blagojevich about his appointment to the seat.

Then, during his testimony under oath in the State Capitol on Jan. 8, he said he recalled a conversation months earlier about his interest in the Senate seat, which was still occupied by Mr. Obama, with a former Blagojevich chief of staff, Lon Monk.

The disclosure Saturday marked the first time that Mr. Burris has acknowledged any contact with Blagojevich confidants during the period when federal authorities say Governor Blagojevich was trying to figure out how much he could get in return for the Senate seat. Mr. Blagojevich, who was removed from office last month, has proclaimed his innocence on the federal charges.

The Chicago Sun-Times first reported the new disclosure by Mr. Burris on Saturday, saying that he had provided a copy of the sworn statement to the newspaper on Friday in response to questions about his contacts with the Blagojevich camp about fund-raising.