Italy's UniCredit bank has confirmed that U.S. authorities are investigating its German unit for possibly breaking economic sanctions, but stopped short of naming Iran as the country it was dealing with.

The Financial Times over the weekend reported that the probe was into suspected sanctions violations involving Iran, which is under international pressure because of its nuclear ambitions.

UniCredit noted Monday that it first disclosed the existence of a U.S. probe in its 2011 financial statements and more recently in a capital increase prospectus, though it did not provide details.

It says HypoVereinsbank (HVB), which joined UniCredit Group in 2005 and now operates as UniCredit Bank A.G., is cooperating with the probe. UniCredit says it can't further comment since the probe and HVB's own review are ongoing.