A French tourist has been kidnapped in Algeria by a militant group linked to Islamic State (IS), French Foreign Minister Laurent Fabius has confirmed.
Algerian militant group Jund al-Khilafa threatened to kill him if France did not halt air strikes on Iraq.
Mr Fabius said an online video that showed Mr Gourdel flanked by armed men was authentic.
He said France would do everything it could to liberate Mr Gourdel, but that the situation was "extremely critical."
Earlier, Islamic State militants warned they would target France - and other countries - after French jets launched air strikes in Iraq against the group.
IS jihadists have seized large swathes of territory in eastern Syria and across northern and western Iraq, forcing tens of thousands of people to flee their homes this year.
French Prime Minister Manuel Valls said there would be "no discussion, no negotiation" with the kidnappers. "If you give in, if you go back one inch... you give [terrorism] this victory," he told French radio while on a visit to Germany on Tuesday.