The Italian foreign ministry says it believes a group of hostages in Nigeria - including one British national - are dead, according to an Italian news agency.
Ansa quoted from an Italian foreign ministry statement which said all seven hostages had been killed.
The Italians said checks carried out in cooperation with the other interested countries led them to believe news of the killing of the hostages taken last month in Nigeria was true.
The statement said: "It is an atrocious act of terrorism, against which the Italian Government expresses the most firm condemnation, for which it can find no explanation, except barbarous and blind violence."
The British Foreign Office said it was "urgently investigating" claims by a breakaway Islamic extremist group that said it killed seven foreigners whom its members kidnapped from northern Nigeria.