"According to what we know, the French hostage is alive. Now we should beware because we do not know exactly the conditions under which it (the abduction) happened," the minister said.

"We do not know if it's a group that kidnapped him for resale to another group or that are people from North of Mali who did that," he added.

Speaking in an interview to BFMTV channel news, the top diplomat urged French citizens to avoid western Mali "because it is extremely unwise to go there."

A 61-year-old Portuguese-born hostage was abducted by armed men on Tuesday in Kayes in southwest Mali while he crossed by car into the country from Mauritania.

The Movement for Oneness and Jihad in West Africa (MUJAO) claimed responsibility for the kidnapping as response to Paris' continued support of a planned military operation to oust Islamists insurgents who controlled the northern region of Mali.

Six French nationals are already in the hands of kidnappers in the Sahel region.