The marines boarded the plane at 5:00 am, the Kochi airport authorities said.
The marines -- Massimiliano Latorre and Salvatore Girone -- secured their passports from Kollam Additional District Sessions court on Friday after submitting an unconditional joint undertaking to return to the state by January 10 and appear before the trial court in Kollam on January 15.
The Italians also executed Rs 6 crore bank guarantee as directed by the Kerala high court on Thursday allowing them to leave for two weeks, following which they sent necessary clearances.
The marines, were arrested on February 19 after they shot and killed two Indian fishermen -- Ajesh Binki (25) and Jelestine (45) -- off Alapuzha coast on February 15 from the merchant vessel 'Enrica Lexie.'
Italian Defence Minister Giampaolo Di Paolo was in Kochi last weekend to meet the marines.
Italian President had also spoken to the marines through video conferencing two days ago.
The Congress-led UDF government on Friday came under attack from Marxist veteran V S Achuthanandan for not challenging the court order.
The Kerala government had on December 18 opposed the plea by the marines to facilitate their visit to Italy, saying it was a ruse to "smuggle them out" and would "torpedo" the ongoing trial.
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