* Marines were allowed home to vote in February election
* Accused of shooting men after mistaking them for pirates
* No response to requests for diplomatic solution - Italy (Adds comment from Indian government)
ROME, March 11 (Reuters) - Two Italian marines charged in India with killing two fishermen while on anti-piracy duty will not return there from a home visit granted to allow them to vote in last month's election, the Italian Foreign Ministry said on Monday.
The ministry said India had not responded to Italian requests to seek a diplomatic solution to the case and there was now a formal dispute between the two countries over the terms of the U.N. Convention of the Law of the Sea.
"Italy has informed the Indian government that, given the formal initiation of an international dispute between the two states, the marines Massimiliano Latorre and Salvatore Girone will not return to India at the end of their home leave," the ministry said in a statement.
Italy was ready to seek a settlement of the dispute through arbitration or an international court decision, it said.
The two sailors, part of a military security team protecting the tanker Enrica Lexie from pirates, were accused of shooting the two fishermen after mistaking them for pirates off the southern Indian state of Kerala in February last year.
The incident has caused a serious diplomatic dispute between Italy and India, which have traditionally had good relations.
An Indian foreign ministry spokesman told Reuters the government would study the message from Italy's ambassador in New Delhi before commenting.
"We have received a communication from Italy late tonight. We will examine it carefully," he said.
India's Supreme Court said in a long-awaited ruling in January that India had jurisdiction to try the marines but Italy has challenged that decision, arguing that the shooting took place in international waters.
The sailors arrived back in Italy on Feb. 23, a day before the country's election, after India's Supreme Court granted their request to exercise their right to vote. They were allowed to remain in Italy for four weeks.
They also spent Christmas in Italy, after a Kerala court allowed them to join their families for the holiday, on condition they returned to India by Jan. 10, which they did. (Reporting by James Mackenzie and Matthias Williams in New Delhi; Editing by Louise Ireland)