President Barack Obama on Friday called the attacks in Paris an "outrageous attempt to terrorize innocent civilians."
"This is an attack on all of humanity and the universal values we share," Obama said from the White House, where he spoke after a slew of attacks that left dozens of people dead and injured.
Three separate shootings have been reported, and there was an explosion outside the Stade de France, where the French national soccer team was playing Germany.
Police have not confirmed whether the attacks are connected, or if they're terrorism-related. But US security officials told Reuters they believe the attacks were coordinated, and experts have said that it's possible that a terrorist group is behind the attack.
Obama said he did not want to speculate about who might be responsible for the attacks.
"It appears there still may be live activity" in Paris, he said.
Obama was been briefed on the unfolding situation by Homeland Security Adviser Lisa Monaco, a White House official said earlier Friday. The attacks come two weeks before Obama and other world leaders are due to travel to Paris for climate talks.
He said in his remarks that the US would stand with France in the face of the attacks.
"We're going to do whatever it takes ... to bring these terrorists to justice," he said.
