A somber President Obama, speaking Friday evening from the White House, vowed to pursue those responsible for the Paris  attacks and protect the United States.

“We are going to do whatever it takes to work with the French people and with nations around the world to bring these terrorists to justice and to go after any terrorist networks that go after our people,” Obama said.

Obama spoke even as running gun battles and explosions continued to rock Paris and it was still unclear who exactly was responsible for the attacks or how many people had been killed. French media reported at least 140 people died in the wave of attacks.

The president kept his remarks brief, expressing solidarity with the French people and promising to provide the French government any counter-terrorism support that it needed. Beyond calling the attack an act of “terrorism,” he declined to speculate on who was responsible, noting that “it appears that there may still be live activity and dangers that are taking place as we speak.”

The president is scheduled to leave tomorrow for the Group of 20 summit in Turkey where the battle against the Islamic State, the refugee crisis and the ongoing wars in Iraq and Syria were already going to be on the top of the agenda of what is normally an economic conference. The attacks in Paris, which come shortly after the apparent downing of a Russian plane in Egypt two weeks ago, will likely will heighten the global leaders' focus on terrorism issues.

The president was briefed on the Paris attacks Friday evening by Lisa Monaco, Assistant to the President for Homeland Security and Counterterrorism. No groups have formally claimed responsibility for the attacks.

The president avoided speculating on who might be responsible for the attacks, and instead spoke of America's longstanding partnership with the French people. He  expressed condolences for the victims' families,  described the French government as as an “extraordinary counterterrorism partner” and praised the city of Paris as representative of  "the timeless values of human progress."

"Those who think they can terrorize the people of France or the values that they stand for are wrong," Obama said.

Obama said he spoke with French President Francois Hollande prior to the attacks Friday in preparation for the upcoming summit, but didn't plan with speaking with him again on Friday. “My expectation is that he is very busy at the moment,” Obama said.

With hostages still being held in Paris and the shooting rampages still ongoing, there was little Obama could do or say beyond expressing a grim solidarity with the French people.

“This is a heartbreaking situation and obviously those of us in the United States know what it’s like,” he said. “We’ve gone through these kinds of episodes ourselves.”