Giorgio Napolitano has questioned Britain's failure to inform Rome before embarking on the failed raid to free the hostages in Nigeria.
The Italian President was speaking at a press conference on Friday.
According to Reuters, Napolitano called British action "inexplicable behaviour" and has demanded answers as to why the Italian government was not informed before the raid that resulted in the death of Chris McManus and Franco Lamolinara.
"The behaviour of the British government in not informing Italy is inexplicable," Napolitano said, adding that a "political and diplomatic clarification is necessary".
However, a Downing Street spokesperson said that the Italian government had been informed before the operation and made no attempt to stop it.
Asked if David Cameron had "apologised" to Mario Monti for the UK's handling of the situation, the spokesperson said "No".
Britain and Italy had been in contact ever since the men were first kidnapped last May, and the Government's Cobra emergency committee had met around 20 times to discuss the case, said the spokesperson.
"We contacted the Italians yesterday as the operation was getting under way, but this was a very fast-moving situation," he added.
"Our priority was to respond to the situation on the ground and to do everything we could to try and secure the safe release of the hostages."
The UK's ambassador in Rome is understood to be in contact with Italian authorities, but Downing Street said it had so far received no official complaint from the government of Prime Minister Mario Monti.
On Thursday, Italian politician Lucio Malan, of the Italian People of Freedom party, questioned why the British government did not inform Italian counterparts of its intentions before launching the operation.
In a statement, Cameron said that he had authorised a rescue mission to go ahead today, saying there was "reason to believe that their lives were under imminent and growing danger."
"Preparations were made to mount an operation to attempt to rescue Chris and Franco. Together with the Nigerian Government, today I authorised it to go ahead, with UK support,” he said.
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