The mayor of Rome has been hospitalized overnight after falling ill.

City hall officials confirmed Tuesday that Ignazio Marino was recovering at Rome's Gemelli hospital, but declined to give the cause. The ANSA news agency said he was suffering from renal colic, a painful condition often caused by kidney stones.

Marino has been coping with the fallout of a massive corruption scandal involving city officials from previous administrations accused of colluding with mobsters to win lucrative municipal contracts for everything from garbage disposal to immigrant reception centers.

A former transplant surgeon, Marino has shrugged off death threats related to the investigation and continues to ride around town on his bicycle.