Islamic extremists will haunt Britain if not stopped: Cameron

British Prime Minister David Cameron has warned that if no action was taken against the militant group Islamic State in Iraq, they could bring terror to the streets of Britain, media reported.

The West is embroiled in a generational struggle against a poisonous brand of Islamic extremism, Cameron warned in an article published in The Sunday Telegraph.

The British prime minister said the world cannot turn a blind eye to the creation of an extremist caliphate in Iraq.

Writing in the newspaper, Cameron said the Islamic State fighters already control thousands of square miles of territory on the shores of the Mediterranean and if these "warped and barbaric" extremists are not dealt with now, they will create a "terrorist state".

He added that Britain will have to use its "military prowess" to help defeat "this exceptionally dangerous" movement, or else terrorists will target people in Britain.

The prime minister said he fears the struggle will last "the rest of my political lifetime".

"The creation of an extremist caliphate in the heart of Iraq and extending into Syria is not a problem miles away from home. Nor is it a problem that should be defined by a war 10 years ago. It is our concern here and now," he said.

In his article, Cameron said Britain and the West needed a firm security response to the crisis in Iraq and that fighters from the Islamic State (IS) cannot simply be removed by air strikes alone.

He wrote that this must involve military action to go after the terrorists themselves, but also stressed that the government must take uncompromising action against extremists in Britain trying to recruit fighters for jihad abroad.

Cameron added that his government has already taken down 28,000 pieces of terrorist related material from the web.