Italy warned on Monday that India's relations with the European Union would be seriously damaged if New Delhi decides to use strict anti-piracy laws to try two Italian marines accused of killing two fishermen during a security operation in 2012.
The sharply worded warning from Prime Minister Enrico Letta came as authorities in India announced that the Supreme Court would hold a hearing next week on whether to charge marines Massimiliano Latorre and Salvatore Girone under strict anti-piracy legislation.
"Italy is not a terrorist country," a statement from Letta's office said, adding that any decision to try the two under anti-piracy legislation would be "absolutely unacceptable".
"It would bring about negative consequences in relations with Italy and the European Union, with equally negative repercussions on the global fight against piracy."
The two marines, part of a military security team protecting the tanker Enrica Lexie from pirates, were accused of shooting the two fishermen after mistaking them for pirates off the southern state of Kerala in February 2012.
Read: Italy objects to Indian piracy law in marine case
The case has embittered relations between Italy and India, with Letta's government under growing pressure from opposition parties to act to bring home the men, who have been living in the Italian embassy in India for much of the past two years while the case against them has been prepared.
Latorre and Girone say they thought the fishermen were pirates and fired shots to warn them off approaching the ship but deny killing anyone.
India's attorney general said on Friday the two would be tried for the deaths of the fishermen under anti-piracy and anti-terrorism laws but that the death penalty would not be imposed.
The Supreme Court is due to hold a hearing on February 18 to decide whether to validate or reject the attorney general's request.
"This is a decision that would harm Italy's dignity as a sovereign state," the statement from Letta's office added.
The Italian government approached India's Supreme Court last month to demand that the marines be allowed to return home, given that charges are yet to be filed two years after the alleged incident. It also sought to block use of the anti-piracy law.