The Italian Foreign Ministry summoned the Indian ambassador Tuesday to protest over the jailing in India of two Italian marines suspected of shooting two fishermen they believed to be pirates.

The summoning of Ambassador Shri Debabrata Saha further escalated a dispute between the two countries over the incident last month. Foreign Minister Giulio Terzi said the jailing of the men was unacceptable.

The two marines were assigned to protect the Italian merchant vessel Enrica Lexie, which was sailing off the Indian coast when they opened fire to avert what they thought was a pirate attack.

The marines, Massimiliano Latorre and Salvatore Girone, handed themselves in to authorities in the southern coastal town of Kochi after the incident and were held in a police-guarded guest house before being transferred to a prison Monday.

Italy, which sent an envoy to negotiate their release, insists that India has no jurisdiction over the matter because it occurred in international waters.

It argues that, since the marines were aboard an Italian vessel, any investigation or trial should be conducted by Italy according to international law governing the high seas.

In New Delhi, the Indian foreign ministry re-stated its position that jurisdiction was theirs.

Our views are very clear on this. The law of the land is taking its course, said spokesman Syed Akbaruddin.

Rome began assigning military teams to protect its merchant vessels in the Indian Ocean last year after a series of attacks by Somali pirates on Italian ships.

Pirates operating in small fishing vessels and fast motorboats have hijacked dozens of ships in the region in recent years, extracting millions of dollars in ransom.

(Reporting By Roberto Landucci and Philip Pullela in Rome; Additional reporting by Satarupa Bhattacharjya in New Delhi; Editing by Robin Pomeroy)