Diplomatic sources said the call was made in distress as the National Investigation Agency has slapped murder charges, which attracts a maximum of death penalty, on the marines.
Monti spoke to External Affairs Minister Salman Khurshid and reminded him that the Italian marines were sent to India on the premise that they will not be tried for murder and will not get death sentence.
Sources said Khurshid told Monti that the Indian law will take its own course but it will be fair. He also told Monti that the case is being fast tracked and repeated the assertion that it does not fall in the "rarest of rare" case.
Monti also holds the charge of the foreign minister, but it is rare that a PM speaks to a foreign minister on a bilateral issue, given the importance of protocol in diplomacy.
The call by Monti followed a meeting between Khurshid and Italian Deputy Foreign Minister Staffan de Mistura, who conveyed to the minister Rome's concern over the fresh developments in the case. Khurshid, in Parliament last month, had ruled out that case will attract a death penalty.
He informed Mistura of the steps being taken in compliance with the SC directions in the last hearing and the intention of the government to inform the apex court on April 16 of the efforts made to constitute a special court, the sources added.