Britain joins fight against ISIL in Iraq

British lawmakers voted on Friday to join the U.S.-led coalition of nations launching airstrikes against the Islamic State of Iraq and the Levant (ISIL) in Iraq, committing warplanes to the fight, but steered clear of joining efforts to target the armed group in Syria.

Prime Minister David Cameron described the move as critical to national security, arguing that facing down the Al-Qaeda splinter group has become a matter of urgency.

"This is about psychopathic terrorists that are trying to kill us and we do have to realize that, whether we like it or not, they have already declared war on us," he said. "There isn't a 'walk on by' option. There isn't an option of just hoping this will go away."

His plea spelled out the consequences of inaction in drastic terms — noting that the group has beheaded their victims, gouged out eyes and carried out crucifixions to promote goals from the "Dark Ages."

The British leader also said a strategy was needed to deal with the radicalization of young people in Europe.

"Young people have left our country to go and fight with these extremists. We must take action at home, but we must also have a comprehensive strategy to defeat these extremists abroad," he said.

Al Jazeera’s Barnaby Phillips, reporting from London, said British involvement in Iraq was expected and U.K. fighter jets had carried out reconnaissance missions over the country in the past few days.

ISIL’s beheading of British aid worker David Haines last month had swayed the public into supporting British intervention in Iraq, Phillips added. His murder, released on video, followed the killing of two American journalists, James Foley and Steven Sotloff, in a similar manner.

Friday’s vote, 524-43, did not address any action in Syria – where ISIL is headquartered – though many lawmakers tried to push the government to admit that taking on fighters there would be the likely next step.

Cameron justified action in Iraq as lawful because the Iraqi government had requested it, but some critics say action in Syria would be illegal because Syrian President Bashar al-Assad has not invited outsiders to help stamp out the group.

Foreign Secretary Philip Hammond refused to speculate on how long the military campaign could last, but lawmakers envision a long-term action.

Earlier in the day, Belgium and Denmark also voted to join the coalition.

The U.S. has been bombing ISIL bases  in Iraq since last month. On Tuesday, it extended its fight against the group to Syria. Arab states – including the United Arab Emirates and Jordan – participated in the campaign.

The air raids follow growing alarm in Western and Arab capitals after ISIL swept through a swath of Iraq in June, proclaimed a caliphate, slaughtered prisoners and ordered Shia and non-Muslims to convert or die.

Al Jazeera and wire services