Italy's outgoing Prime Minister Mario Monti said on Wednesday that "safety" was behind the decision to send back two Italian marines to India where they face murder trial, a day after Foreign Minister Giulio Terzi quit out of disagreement with the government.

"Our priority was safety, security and dignity of our two marines as well as of all Italians who are in India," Monti said in an address to parliament. There were "serious and objective risks" that Italy could remain "isolated in the international community amid a crisis of grave proportions with India," he said.

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

The marines have been at the center of a bilateral dispute since February 2012, when they were arrested in India with charges of shooting dead two fishermen while on anti-piracy duty off its southern coast. While Italy insists the accident happened in international waters, India claims that Latorre and Girone should be tried on its territory.

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 also 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 on Wednesday, said that 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."

Later in the day, Terzi denied media reports which said he may aim to a political career with former Prime Minister Silvio Berlusconi's center-right People of Freedom (PdL), which was particularly critical of the government's confused 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," he said.

According to local analysts, however, to turn the issue into material for political controversy would be only the last in a "long series of mistakes over the issue" and exactly what the marines asked not to be done in their appeal to the unity of sides.

Not opposing the shoring of the two officers, having accepted an agreement to then violate it, and finally breaking the word given to two servants of the state was an unacceptable "sequence of errors," said Vittorio Emanuele Parsi, a professor of international relations at the Catholic University of Milan and columnist of Il Sole 24 Ore financial newspaper.

"Whatever the deep reasons be why the case was managed so badly, my opinion is that there was not a shared line within the government," an associate research fellow of ISPI institute of international politics, Andrea Carati, told Xinhua.

As a result, though the relations between Italy and India are expected at the end to remain as good as traditionally, the credibility of the Italian diplomacy came out "quite deteriorated," he said. This cannot but be "an objective view shared by both common citizens and diplomacy experts," Carati added.