Al-Qaeda has warned Paris not to attempt to rescue five French nationals kidnapped in Niger.
France says it has put together a full-scale military, diplomatic and intelligence operation to secure the release of seven hostages.
They were kidnapped from a uranium mine in northern Niger on 16 September by the al-Qaeda in the Islamic Maghreb group.
The hostages are now believed to have been taken to north-eastern Mali.
France's foreign ministry has confirmed that a claim from AQIM that it took the latest hostages is genuine.
A new statement attributed to the group appeared on Islamist forums on Thursday, warning France against trying to rescue its citizens.
France's national police chief Frederic Pechenard has warned that the country is facing a "peak" terror threat, such as a conventional bomb attack on a crowded target, and he named AQIM as a particular threat.
"France is today under threat," he told Europe-1 radio on Wednesday.
"We're now facing a peak threat that can't be doubted. There is a specific threat against French interests."
"AQIM was "targeting (France) in particular," he said.