Massimiliano Latorre and Salvatore Girone have been accused of killing two Indian fishermen.

An international arbitration court on Monday began hearing Italy's request to direct India to drop all criminal charges against two of its marines, accused of killing two Indian fishermen off the Kerala coast in 2012 and grant Rome jurisdiction in the case.

Italy took the issue to the Permanent Court of Arbitration in The Hague in 2015, saying the case should be tried under maritime law. India, however, insists that the accused should return to New Delhi for a final judgement by an Indian court.

Presently, the two marines - Massimiliano Latorre and Salvatore Girone - are in Italy.

Italy's representative Francesco Azzarello told the court on Monday that Rome should have jurisdiction over the case because the two marines were functionaries of the Italian state doing their duty on board an Italian flagged ship in international waters.

"In India's eyes there is no presumption of innocence: the marines were guilty of murder even before the charges were laid," he was quoted as telling the court by Italian news agency ANSA.

He also said, "there were unjustifiable postponements of the trial in India. Special procedures were invented in violation of the Indian Constitution."

In response, India's representative G Balasubramanian told the court, "Italy maintains it has the exclusive jurisdiction in the case but one must take into account the fact that India and the two fishermen are the victims in this case."

He said two fishermen aboard an Indian boat were killed by individuals who were on a merchant ship.

On Italy's claims that the marines fired warning shots into the water to deter the boat, he said, "it is difficult to believe that these volleys were simply meant as warning shots...They hit two crew members, caused damage to the boat, endangering its safe navigation, and also endangering the lives of the other nine crew members."

On Italy's allegations of delay in the Indian court proceedings, he said, "...the reality of the fact forces me to say that had Italy cooperated with the prosecution of the killing incident, this case would have been finally concluded long ago."

He said Italy initially joined the proceedings before the Indian courts but surprisingly in a negative way, hampered them by filing multiple interlocutory applications challenging the actions of the Indian authorities.

"The case proceeded in the Indian courts, first before the Kerala court and then before the Supreme Court followed by the establishment of a special court for that purpose.

"Adopting a negative posture, however, Italy chose the cause of delaying it further by filing continuous applications which are nothing but designed to thwart the special court...," the Indian representative told the court.

He recalled that Salvatore Girone was allowed to reside at the residence of the Italian ambassador in New Delhi and said, "This clearly articulates how reasonable and cooperative India has been treating the marines and Italy during the proceedings before the Indian courts."

The marines were aboard the Italian-flagged commercial oil tanker ''Enrica Lexie'' when they killed the two Indian fishermen.

The complaint against them was lodged by Freddy, the owner of fishing boat ''St Antony'' in which the two Kerala fishermen were killed when the marines opened fire on them allegedly under the misconception that they were pirates.

Massimiliano Latorre, who had suffered a brain stroke on August 31, 2014, was first granted bail and allowed by the Supreme Court on September 12, 2014 to go to Italy for four months and after that, extensions have been granted to him.

In Italy, Massimiliano Latorre had to undergo a heart surgery after which the top court had granted him extension of his stay in Italy

On September 28, 2016, the top court had allowed Latorre to remain in his country till the international arbitral tribunal decided the jurisdictional issue.

On May 26, 2016, Salvatore Girone was also granted bail and allowed by the Supreme Court to go to his country till the jurisdictional issue was decided.