Barack Obama: Terror attack aimed at France and 'all of humanity'

President Barack Obama vowed to help hunt down those responsible for "terrorism and extremism" in Friday's Paris terror attacks, saying Americans know well how the French feel.

"Once again, we've seen an outrageous attempt to terrorize innocent civilians," Obama said in brief statement from the White House. "This is an attack not just on Paris, it's an attack not just on the people of France, but this is an attack on all of humanity and the universal values that we share."

French authorities have said as many as 60 people have been killed in a Paris restaurant and in a concert hall, where hostages were taken, but the scope of the attacks remained unclear Friday night and may involve more than two locations.

"This is a heartbreaking situation," Obama said, calling France this country's oldest ally.

"Obviously those of us here in the United States know what it's like. We've gone through these kinds of episodes ourselves. And whenever these kinds of attacks happened, we've always been able to count on the French people to stand with us. They have been an extraordinary counterterrorism partner, and we intend to be there with them in that same fashion."

The president declined to say who might be responsible and did not mention any threats to the United States.

"I don't want to speculate at this point in terms of who was responsible for this," he said. "It appears that there may still be live activity and dangers that are taking place as we speak."

Obama said he had not spoken to French President Francois Hollande yet but had coincidentally spoken to him earlier in the day about Sunday and Monday's G-20 financial summit in Turkey.

Minutes after Obama finished speaking, Hollande announced he was closing the borders and declaring a state of emergency. He said operations against the attackers were ongoing and asked for the public's trust in security forces, urging people to stay off the streets for their own safety.