WASHINGTON: US President Barack Obama and British Prime Minister David Cameron agreed Friday to a joint effort to fight domestic terrorism after last week's deadly attacks in France.

Cameron said the shootings in Paris were a reminder that Britain and America face threats to national security from people who hate what the two countries stand for.

“We must also fight this poisonous ideology, starting at home,” Cameron said.

Obama, speaking at a news conference alongside Cameron after two days of meetings, said they spent much of their time talking about the fight against terrorism.

He called the Paris attacks, which killed 17 people, “vicious” and said both the US and Britain stand with the French and all allies fighting the “scourge” of terrorism.

He said the US and Britain will "do everything in our power to help France seek the justice that is needed."

Fears of further violence by Islamic extremists are growing, with police in Belgium saying they killed two suspects in a raid Thursday to stop another major impending attack.

Cameron said, "We know what we're up against and we know how we will win."