Italy called for explanation from Britain on Friday over the handling of a failed operation to save two Italian and British hostages in Nigeria that led to their deaths.

"A clarification is necessary on the political and diplomatic level,"Italy's President Giorgio Napolitano was quoted as saying by local media.

"The behavior of the British government for not having informed and consulted Italy was inexplicable,"he stressed.

According to British Foreign Secretary William Hague, Britain had remained in close contact with Italy but was forced to make a snap decision, while Defense Secretary Philip Hammond replied to Napolitano that the British action was "fully explicable" although painful.

The Italian hostage, 47-year-old engineer Franco Lamolinara working for an Italian company in Nigeria, was killed by kidnappers along with his 28-year-old British colleague Christopher McManus on Thursday during a joint British-Nigerian operation in the northwestern city of Sokoto.

According to the ANSA news agency, Italy's Prime Minister Mario Monti was informed with a telephone call by his British counterpart David Cameron only after the raid had already ended tragically.

On Friday, Monti chaired a security committee meeting aimed at "clarifying with rigor" the circumstances of the raid, after demanding to Nigerian President Goodluck Jonathan a "complete reconstruction" of the operation.

"It needs to be clarified why Britain decided to launch a military operation without informing Italy .. We will get to the bottom of this," said Massimo D'Alema, the president of the Italian parliamentary security committee and a former prime minister.

Cameron reportedly said Friday that he authorized the joint raid as he was warned the lives of the two hostages were in "imminent and growing danger."

According to Nigerian State Security Service, the kidnappers shot the victims before the rescue military team entered the compound they were being kept in.

The hostage-takers were reportedly members of the militant Islamist sect Boko Haram, and had been working with al Qaeda in exchange for training and weapons for their fight to impose Sharia law in Nigeria.

The two victims were kidnapped last May, and appeared in a video in August kneeling before three masked men.