A Paris police official said there were at least 100 hostages in a Paris theater following shooting and explosions at two cites in the city.
Multiple officials, including one medical official, put the number of dead at between 35 to 40 people.
All officials spoke on condition of anonymity because they were not authorized to be publicly named according to police policy.
U.S. Homeland Security Department officials monitoring the attacks in Paris say there is no known, credible threat against the United States.
DHS officials are in contact with their foreign counterparts amid reports of multiple shootings and explosions in Paris.
Police officials in France say at least 26 people have been killed and a hostage-taking situation is underway at a theater.
Two police officials say that at least 26 people have been killed in shootings and explosions around Paris, in the deadliest violence in France in decades.
One of the police officials said 11 people were killed in a Paris restaurant in the 10th arrondissement and about 15 killed in the Bataclan theater, where a hostage-taking is under way.
Both officials spoke on condition of anonymity because they were not authorized to be publicly named according to police policy.