D.C. Council Chairman Phil Mendelson said late Wednesday that he is not calling on Mayor Vincent Gray to resign in the aftermath of revelations that an illegal shadow campaign helped elect Gray.

"The U.S. attorney has not accused the mayor of having broken the law and, absent that charge, the call for Vince Gray to resign is premature," Mendelson said in a statement. "Given the facts we know, the call for the mayor's resignation creates instability at a time when we need stability."

Mendelson issued his statement hours after three D.C. lawmakers - Muriel Bowser, David Catania and Mary Cheh - said that Gray should quit.

"Whether he knew or not about the shadow campaign, the time has come for the mayor to step down," Catania told The Washington Examiner. "We know that his campaign engaged in a criminal conspiracy to undermine the election laws of our city, calling into question the legitimacy of the election and his legitimacy as mayor."

Pedro Ribeiro, a spokesman for Gray, dismissed Catania's remarks as "irresponsible."

Gray is under increasing political pressure after federal prosecutors confirmed Tuesday that he benefited from a $653,800 shadow campaign in 2010.

That shadow campaign is one subject of a lengthy federal probe into the mayor's campaign that has already netted the convictions of three Gray campaign operatives.

Gray has denied wrongdoing, but he acknowledged Wednesday that the shadow campaign was not what he envisioned.

"This is not the campaign we intended to run," said Gray, who told reporters Wednesday morning that he did not plan to resign.