Rome mayor Ignazio Marino on Friday confirmed media reports that he is being probed in two separate investigations, but strongly denied any wrongdoing and claimed he had acted "transparently".
"It is a formal requirement for an investigation - and for a probe to be shelved," Marino commented on the reports he is under investigation.
"I never used public money for personal ends and if anything, I have done the opposite," Marino added.
"I am certain that I have explained my side of the story to magistrates in a transparent way," he said.
Rome-based daily La Repubblica earlier reported that one of the investigations was into allegations Marino paid for private dinners with his municipal credit card while a second probe concerned fraud at a charity he founded.
A day earlier Democratic Party member Marino, withdrew his resignation over the expenses scandal that earlier this month forced him to step down after he lost the support of his party despite his claims that restaurant receipts had been forged.
Rome City Council said that Marino had signed a letter "by which he withdraws his resignation presented on 12 October".
A vote of no confidence in Rome's 48-member municipal council could still force the former surgeon, one of Italy's most unpopular politicians, from Rome's top job.
Rome prosecutors on 6 October began an investigation into Marino's expenses, after petitions filed by two opposition parties.
The rightwing Brothers of Italy party and the grassroots Five-Star Movement allege embezzlement took place.
No individual was initially under investigation in the probe, magistrates said.
