Amidst a diplomatic row with India, Italy has said it is on solid legal ground in seeking international arbitration in the case of the Italian marines charged with killing two Indian fishermen.

"We have juridically solid reasons to proceed in the direction of international arbitration," Italian Foreign Minister Giulio Terzi told reporters as he arrived at an international conference being hosted by an Israeli think-tank in the city of Herzliya.

"The Indian government is amply apprised of all it needs to know about our reasons, as do many of our partners," he was quoted as saying by media reports.

Already-strained relations between Rome and New Delhi notched up on Monday when the Italian government announced that marines Salvatore Latorre and Massimiliano Girone would remain in Italy and not return to India to face murder charges after being allowed to come home to vote in February's general election by the Supreme Court.

The Apex Court had allowed them to go to Italy to cast their vote in the elections there after Italian Ambassador to India Daniele Mancini had given an assurance to send them back.

Prime Minister Manmohan Singh had yesterday noted that the country is agitated over Italy's action which is "unacceptable" and said the government will pursue diplomatic channels to bring the two marines back.

Taking a tough stand, the prime minister also accused Italy of violating "every rule of diplomatic discourse" and asked it to send back the two marines undergoing trial for killing Indian fishermen, failing which there will be consequences on bilateral ties.