The serious and objective risks that Italy could become “isolated in the international community amid a crisis of grave proportions with India” over the two marines led the Italian government to decide to send them back to India, outgoing Prime Minister Mario Monti has said.

The two marines - Massimiliano Latorre and Salvatore Girone - have been at the centre of a bilateral dispute since February 2012, when they were arrested in India on charges of shooting two Indian fishermen dead while on anti-piracy duty off its southern coast.

While Italy insists the incident happened in international waters, India claims that Latorre and Girone should be tried as the crime appeared on its territory.

“Our priority was safety, security and dignity of our two marines as well as of all Italians who are in India,” Xinhua news agency quoted Monti as saying in an address to parliament, a day after Foreign Minister Giulio Terzi quit out of disagreement with the government.

Monti said there were “serious and objective risks” that Italy could remain “isolated in the international community amid a crisis of grave proportions with India”.

On Tuesday, Terzi abruptly resigned claiming that his voice went “unheard” as the caretaker cabinet decided to send back Latorre and Girone 10 days after it reneged on a pledge to return the two men who had been granted a four-week leave.

Monti said that the U-turn decision, which was sparked by an escalating row in which India ruled that the Italian ambassador could not leave the country without permission, has reopened bilateral talks that can lead to “a quick solution”.

He rejected “speculations” linking the case to economic interests surrounding a controversial contract for the purchase of Italian helicopters by the Indian government.

Monti, who was sworn in as temporary foreign minister Wednesday, said he was “stunned” by the fact that Terzi gave no warning he would step down, adding that his real goal could “become clearer in the near future”.

Terzi has denied media reports which said he may aim at a political career with former prime minister Silvio Berlusconi’s People of Freedom party, which was particularly critical of the government’s handling of the case.

“There was no personal purpose. Being it a story that got me involved at the institutional and personal level, I felt it was impossible to continue my commitment,” Terzi said.