India has demanded the return of two Italian marines to face trial for homicide in the country. It rejected the stand of the Italian government which has gone back on its assurances.

Angered by a sudden U-turn by the Italian government which refused the return of two marines, charged with killing of two Indian fishermen last year, the Ministry of External Affairs summoned the Italian Ambassador Daniele Mancini to convey New Delhi's position on the issue in the strongest terms.

The summoning came a day after the Italian Foreign Ministry refused the return of the two marines, accusing Indian authorities of violating international rights by detaining the marines.

It said it was open to letting an international arbitrator assess the case. Foreign Secretary Ranjan Mathai, after his meeting with the Italian Ambassador, told reporters that Italy is obliged to send back the marines.

Prime Minister Manmohan Singh has also described Italy's decision as unacceptable.