US and France to step up airstrikes in Syria in wake of Paris attacks

The US and France have agreed to step up airstrikes in Syria and Iraq to target Islamic State in the wake of the deadly attacks in Paris, French President Francois Hollande said.

In a joint press conference with US President Barack Obama at the White House, Hollande said airstrikes would be stepped up but France would not put troops on the ground in Syria.

Obama said the US and France stand united in the fight against IS, which "poses a serious threat to all of us."

"The United States and France stand united, in total solidarity, to deliver justice to these terrorists ... and to defend our nations," Obama said.

He said he agreed with France that more needed to be done to combat IS.

"US assistance has supported recent French strikes in Syria and we're going to keep stepping up that coordination," Obama said.

"We will continue to do everything in our power to defend our nation.

"We will win and groups like IS will lose.

"Viva la France."