|Antoine de Leocour, left, and Vincent Delory were killed after French special forces failed to rescue them [Reuters]
The French prime minister has said he is almost certain that al-Qaeda in the Islamic Maghreb was behind the abduction of two Frenchmen killed in Niger over the weekend.
Francois Fillon's remarks came two days after the pair were found dead, apparently killed by their kidnappers on Saturday, after French special forces joined a failed attempt to rescue them in the African state.
The bodies were charred with their hands tied behind their backs, according to two hospital sources in Niger who had seen them.
"We are almost certain that it was AQIM," Fillon said on Monday, referring to al-Qaeda's north African affiliate.
The two victims were abducted from a bar, bringing to eight the number of French people snatched in Niger since April.
They were the first to be seized in the capital Niamey, far from the lawless desert where al-Qaeda-linked fighters, rebels and bandits all operate.
Toure Aminata Djibrilla Maiga, Niger's foreign minister, said in Ouagadougou, Burkina Faso's capital, that Niger would not relent in combating terrorism.
"Niger is determined to fight terrorism in all of its forms. The army is engaged and will continue its combat against terrorism with the full support of the population," Maiga said.
He said that three Nigerien soldiers were killed in the rescue attempt, along with four of the kidnappers.
Alain Juppe, the French defence minister, travelled to Niamey on Monday to meet Niger authorities and the French community. France has around 1,550 nationals in Niger.
A high-ranking Nigerien military official told the Reuters news agency the two hostages had probably been executed before French and Niger forces clashed with the kidnappers, as their bodies were found some distance away.
"They were coldly eliminated, according to the initial information that I have," Fillon said. "Of course the investigation will be deepened and the results will be made known to the families."
Asked about two French journalists taken captive by the Taliban in Afghanistan a year ago, Fillon said: "I think there can only be a favourable outcome there."
A security official in neighbouring Mauritania, where AQIM also operates, told Reuters that three of the kidnappers were captured alive by the French and Nigerien joint force.
AQIM, which operates across West and North Africa's vast Sahara desert, is holding another five French citizens, employees of French firms Areva and Vinci, taken from the northern mining town of Arlit in September.
AQIM also killed a French tourist, Michel Germaneau, in July after kidnapping him in Niger three months earlier.