President Obama and French President François Hollande promised to increase cooperation and expand attacks against the Islamic State in Syria and Iraq.
During a joint press conference with Hollande at the White House, Obama said that the United States and France "owe our freedom to each other."
After the Paris attacks, Obama said, "our hearts broke too."
"In that stadium, concert hall, restaurants and cafes we see our own," Obama said. "Today we stand with you."
Hollande arrived in Washington on Tuesday to talk to Obama about building a more robust international coalition to combat ISIS. Hollande is trying to get the big international players — mainly the U.S., Russia and Germany — on the same page.
Hollande will meet with German Chancellor Angela Merkel on Wednesday and Russian President Vladimir Putin on Thursday.
On Morning Edition, NPR's Scott Horsley explained that Hollande is trying to bridge a tough divide: the United States and Russia have a fundamentally different view of the civil war in Syria.
"While Russia sees Syrian President Bashar Assad as a bulwark against terrorism, Obama sees the Syrian president as a recruiting tool for the group. Every time Assad attacks his own citizens, Obama says, it drives more people into the arms of ISIS. Middle East analyst Aaron David Miller of the Woodrow Wilson Center says bridging those different viewpoints will not be easy, but only Russia has the necessary leverage if Assad is to be pushed out.
"'For better or worse, right or wrong, [the U.S. needs] Putin if there is going to be any resolution and any kind of political transition in Syria," Miller said."
Hollande stood with the United States during the press conference saying in no uncertain terms that Assad has to go.
"Bashar Assad cannot be the future of Syria," Hollande said. "Assad has been the problem so he cannot be part of the solution."
Hollande added that the United Nations Security Council has passed a unanimous resolution to fight the Islamic State and he believes that means Russia has to refocus in Syria to attack Islamic State targets.
Obama said that given Russia's "military capabilities and the influence they have with Assad, their cooperation would be helpful."
But, Obama said, the United States already has a robust coalition of 65 countries fighting against the Islamic State.
Obama and Hollande were both asked if they could set a deadline for Assad's exit. Both presidents declined.
"We have to let the Vienna process play itself out," Obama said, referring to an agreement among 17 countries that lays out a timeline for a political transition in Syria. "It is our best opportunity."
Obama also said that any political transition would be a "long, methodical process" that both the U.S. and France are committed to.
"It's going to be hard and we should not be under any illusions," Obama said. "Syria has broken down; it began to break down the minute that Mr. Assad" started to kill his own people, Obama said.