Britain's PM David Cameron recalls parliament to sanction air strikes against Islamic State

Prime Minister David Cameron said he wanted Britain to join US-led air strikes against the Islamic State militant group after the Iraqi government requested London's help and he recalled parliament to secure its approval for military action.

Parliament, which was in recess, will reconvene on Friday to vote on allowing Britain's Royal Air Force to hit Islamic State targets in northern Iraq. The action has the backing of all three main parties and is expected to comfortably pass.

Cameron spoke after US planes pounded Islamic State positions in Syria for a second day. But the strikes did not halt the fighters' advance in a Kurdish area where fleeing refugees told of villages burnt and captives beheaded.

"We must not be so frozen with fear that we don't do anything at all," Cameron told the 193-member United Nations General Assembly on Wednesday. "We have a need to act in our own national interest to protect our people and our society. So it is right that Britain should now move to a new phase of action."

He described Islamic State as having a "sick extremist world view."

Britain, a staunch US ally, was quick to join military action in Afghanistan and Iraq a decade ago. But a war-weary public and parliament's rejection last year of air strikes on Syrian government targets prompted Cameron to proceed cautiously this time and win cross-party support before acting.

"What we are doing is legal and it is right. It does not involve British combat troops on the ground," Cameron said earlier in New York. "I'm confident we will get this through on an all-party basis."

Cameron said the Iraqi government had requested British air strikes. He met with Iraqi Prime Minister Haider al-Abadi earlier on Wednesday at the United Nations.

"Our enemies' enemy not our friend"

Cameron, who is up for re-election next year and is keen not to roil public opinion, will hold a detailed discussion with his Cabinet on Thursday in London about the kind of military action he envisages.

A few months ago, the British government was not actively considering air strikes. But the beheading of a British aid worker by an Islamic State militant with a British accent has highlighted the danger the group poses to domestic security.

Cameron has been clear, however, that Britain would not yet take part in any air strikes against Islamic State militants in Syria and that, if he decided to do so, he would organise a separate parliamentary vote to get lawmakers' backing.

That could be problematic because the opposition Labour party has said it is not yet ready to support such strikes and would require a UN resolution beforehand.

Some lawmakers have also expressed concerns about the legality of hitting Islamic State in Syria without the consent of the Syrian government, which Cameron has made clear he views as illegitimate.

Cameron said it was "dangerously misguided" for anyone to think that a deal could be done with Syrian President Bashar al-Assad in a bid to defeat Islamic State.

"Our enemies' enemy is not our friend. It is another enemy," he said. "Doing a deal with Assad will not defeat (Islamic State) because the bias and the brutality of the Assad regime was and is one of the most powerful recruiting tools for extremists."

Cameron, who has called the risk of British Islamist radicals returning from Syria and Iraq to attack Britain as the biggest national security threat, suggested the beheadings of two US citizens and a British aid worker had stirred public opinion in Britain.

"The shocking murders of James Foley, Steven Sotloff and David Haines by a fighter with an apparent British accent underlines the sinister, direct nature of this threat," Cameron told a UN Security Council meeting on the foreign extremist fighters.

"British people are sickened that a British citizen, a British citizen, could be involved in murdering people," he said.

Islamic State militants are holding another British hostage, aid worker Alan Henning, who they have threatened to murder.