KANO, Nigeria (AFP) - Nigeria on Saturday quizzed the alleged kidnappers of two Westerners killed during a failed British-Nigerian rescue bid amid a diplomatic row between London and Rome over the operation.
A Nigerian security source said one had confessed to killing Italian engineer Francesco Molinara, 48, and his British colleague Chris McManus, 28, during the assault authorised by British Prime Minister David Cameron on Thursday.
The radical Islamist Boko Haram sect, blamed for scores of gun and bomb attacks mainly in the country's northeast in recent months, has denied responsibility for the kidnappings.
Nigerian security sources told AFP eight suspects had been flown to the capital Abuja following the joint military operation in the northern town of Sokoto to free the hostages after almost a year in captivity.
"Those that were arrested in connection with the incident were brought to the SSS (secret police) headquarters, Abuja, yesterday," a security source said.
"In the course of interrogation one of them said they killed the two guys on sighting the security men because they were not sure they, too, will survive the attack," he said.
Another security source said: "They are being interrogated to have a complete picture of the whole episode."
"A lot of substantial information is beginning to emerge from the suspects."
Italy has condemned Britain's failure to warn it ahead of the failed rescue operation, but London said it had been forced by the situation to act swiftly.
"The behaviour of the British government, which did not inform or consult with Italy on the operation that it was planning, really is inexplicable," President Giorgio Napolitano told reporters on Friday.
At an EU foreign ministers' meeting in Copenhagen later Friday, Foreign Minister Giulio Terzi di Sant'Agata said he made Italy's feelings clear during talks with British Foreign Secretary William Hague.
Cameron said the two hostages had been held by "terrorists" who had made "very clear threats to take their lives", and the captives had been in "imminent and growing danger".
Both countries have however agreed to cooperate on the issue.
Nigerian President Goodluck Jonathan has sent his condolences to the British and Italian premiers over the incident.
"In two separate letters of condolence to David Cameron and Mario Monti... President Jonathan said that the hearts of the people and government of Nigeria go out to the members of the immediate families of the victims in their moment of grief," his office said Saturday.
It said Jonathan also assured the two prime ministers of Nigeria's commitment to fight "terrorism".
AFP received a video showing McManus and Lamolinara in August, three months afgter they were snatched from their apartment in Kebbi state, where they were working for construction firm Stabilini Visinoni.
In the footage, both men said their kidnappers were from Al-Qaeda.
In a second video received by a Mauritanian news agency and seen by AFP in December, gunmen threatened to execute McManus if their demands were not met. Jonathan said the kidnappers were Boko Haram members, but the radical sect denied the claim on Friday.
"We are not behind the hostage taking... which led to the military operation yesterday in Sokoto in which the hostages were killed," the group's spokesman Abul Qaqa said in a conference call with reporters.
Witnesses in Sokoto said they did not believe the kidnappers were from the sect.
"Boko Haram is not in operation in Sokoto. It is just kidnappers. It's about money", said Umar Bello, the local chief of Mabera neighbourhood where the shootout occurred.
"Their major priority is money, and if they don't get the money they have nothing to lose."
But a security source insisted Saturday Boko Haram was involved in the incident.
"The mastermind of the kidnap that goes by the name Abu Muhammad is an AQIM affiliate associated with Boko Haram," he said, referring to Al-Qaeda in the Islamic Maghreb.
"The kidnap was orchestrated for purely financial motives. The aim was to raise money from the ransom payment, part of which will go in funding Boko Haram attacks," he said.
The shadowy sect has said it wants to create an Islamic state across Nigeria's deeply-impoverished mainly Muslim north but some analysts believe there are different factions with varying interests.
Diplomats have said some Boko Haram members have sought training abroad, but there has been no evidence of operational links with foreign groups.
Al-Qaeda in the Islamic Maghreb has in recent years claimed kidnappings of expatriate workers in countries including Niger, which borders Nigeria to the north, but never in Nigeria. Sokoto state borders Niger.