An Air France flight AF083 from San Francisco to Paris has been diverted to Montreal after an "anonymous threat".
“The aircraft landed normally. Local authorities will conduct checks,” the carrier said.
Security officials worldwide have been on high alert since Islamic State militants claimed responsibility for attacks in Paris last month that killed 130 people.
Meanwhile, the FBI have said the San Bernardino killers had been radicalised “for quite some time” and had taken target practice at gun ranges, in one instance just days before the attack.
Authorities also disclosed that a year before the rampage, Syed Farook’s co-workers at the county health department underwent “active shooter” training in the same conference room where he and his wife opened fire on them last week.
It was not immediately clear whether Farook attended the late-2014 session on what to do when a gunman invades the workplace, San Bernardino County spokeswoman Felisa Cardona said. Two employees who survived the attack said colleagues reacted by trying to do as they had been trained – dropping under the tables and staying quiet so as not to attract attention.