Britain and the United States are to establish a new joint group to counter the rise of violent extremism in the wake of the Paris terror attacks, David Cameron and Barack Obama have announced.

Following talks in the White House with the US President, the Prime Minister said they were determined to confront the “poisonous and fanatical ideology” of the extremists wherever it occurred.

He said the new UK-US group would look at what more they could do to identify and counter the threat in their own countries while learning from each other’s experience.

At the same time, Britain is to step up its support to Iraqi forces fighting Islamic State (IS) terrorists with the deployment of additional intelligence and surveillance assets.

“Britain and America both face threats to our national security from people who hate what our countries stand for and are determined to do us harm,” Mr Cameron told a joint press conference with Mr Obama.

“In recent weeks, we have seen appalling attacks in Paris, in Peshawar, in Nigeria. The world is sickened by this terrorism.

“So we will not be standing alone in this fight. We know what we are up against. And we know how we will win.

“We face a poisonous and fanatical ideology that wants to pervert one of the world’s major religions – Islam – and create conflict, terror and death. With our allies we will confront it wherever it appears.

“But, most important of all, we must also fight this poisonous ideology, starting at home.”

Mr Obama said that the Paris attacks, which left 17 people dead, underlined the continuing threat from terrorist groups.

“We will continue to do everything in our power to help France to seek the justice that is needed. All our countries are working together seamlessly to prevent attacks and defeat these terrorist networks,” he said.

“The Paris attacks underscored again how terrorist groups like al Qaida and Isil are actively trying to inspire and support people within our own countries to engage in terrorism.

“We both recognise that intelligence and military force alone is not going to solve this problem so we are also going to keep working together on strategies to counter violent extremism that radicalises, recruits and mobilises people, especially young people, to engage in terrorism. “

Mr Obama warned that European countries needed to do more to assimilate their Muslim populations into mainstream society.

“Our biggest advantage is that our Muslim populations, they feel themselves to be Americans. There is this incredible process of immigration and assimilation that is part of our tradition,” he said.

“There are parts of Europe in which that is not the case and that’s probably the greatest danger that Europe faces.”

While Mr Cameron acknowledged the importance of assimilation, he said that even among groups who were well-integrated, people were being recruited by the extremists.

“You can have, tragically, people who have had all the advantages of integration, who have had all the economic opportunities our countries can offer, who still get seduced by this poisonous, radical death cult of a narrative,” he said.