New Delhi, Mar 22 (IANS): Even as the government claimed it was deft "diplomacy" that was responsible for the return of the two Italian marines to stand trial for murder, the opposition Friday said it was the pressure it created that made the difference.

"It was a combined effort of all opposition parties. The opposition persuaded the government, which made it work out a tough stand," Bharatiya Janata Party leader Rajiv Pratap Rudy said.

Taking a similar stand, Communist Party of India leader Gurudas Dasgupta said the government alone could not take credit for the return of the marines.

"It is good Italy is sending them back, but government cannot take the full credit," Dasgupta added.

"The Congress can garland itself if it wants, but the truth is that credit must be given to public pressure, the pressure created by parliament, international pressure, and also to the stand the Supreme Court took," he said.

The two Italian marines facing trial for killing two Indian fishermen last year are headed back to India, the government announced Friday.

Italian ambassador Daniele Mancini had earlier given an undertaking to the Supreme Court that the marines would return to India by March 22 after voting in national elections there, but on March 11 Italy informed India that the marines would not be sent back, setting off a diplomatic row.

The marines, posted aboard oil tanker MV Enrica Lexie on security duty, had Feb 15, 2012, opened fire at a fishing boat off the coast of Kerala, suspecting that the boat carried pirates. Two fishermen, Ajesh Binki and Gelastine, were killed in the firing.