Kim Hjelmgaard

USA TODAY

LONDON — British lawmakers voted overwhelmingly Friday to join the U.S.-led coalition conducting airstrikes against the Islamic State in Iraq, but they did not act on whether to approve strikes against the militants in Syria.

"I believe it is our duty to take part," British Prime Minister David Cameron said in a speech to the House of Commons, ahead of a debate in parliament that lasted about seven hours. "This international operation is about protecting our people, too, and protecting the streets of Britain should not be a task that we are prepared to entirely subcontract to other air forces of other countries," he said.

The vote was 524 to 43 in favor. Authorization to use force in Syria, where U.S.-led airstrikes began this week, will require a separate vote.

During the debate, opposition Labor Party leader Ed Miliband called for a U.N. Security Council resolution before the U.K. considers any action in Syria. That suggests Cameron asked for a narrower vote on Iraq because he could not be certain one covering Iraq and Syria would pass.

"This is not the stuff of fantasy," the prime minister said in his address. He said six terrorist plots across Europe by the group have been foiled in the wake of an attack inspired by the militants on a Jewish museum in Brussels. "It is happening in front of us and we need to face up to it," he said.

Approval for action in Iraq was never in jeopardy. All three main British political parties — Conservative, Labor and Liberal Democrat — signaled they were prepared to endorse a bombing campaign against the Islamic State, also known as ISIL or ISIS, in Iraq partly because Iraq's government has asked for direct assistance.

Cameron has the power to authorize action unilaterally, but he sought explicit parliamentary backing for intervention in Iraq because he suffered an embarrassing defeat last year over an attempt to move militarily against the Syrian regime of President Bashar Assad.

Another factor: In 2003, then-Prime Minister Tony Blair went to war in Iraq against the wishes of many in parliament and a large section of the British electorate.

Demonstrators opposed to British intervention protested outside the prime minister's Downing Street residence on Thursday and Friday.

Separately, Denmark said on Friday that it would join the coalition and send seven F-16 fighter jets to take part in airstrikes against the group in Iraq.

Washington reacted favorably.

"We certainly welcome the recent vote that happened in the British Parliament, indicating their strong support for the plan the president laid out for defeating ISIL," White House Press Secretary Josh Earnest said.

Commenting on Denmark's participation, Earnest said: "That is another welcome development, and one that is indicative of the growing support across the globe for this international coalition that the president vowed to build and lead."

The debate comes as Gilles de Kerchove, the European Union's anti-terrorism chief, said there may be as many as 3,000 European citizens fighting for the Islamist militants in Iraq and Syria. "If you believe in this (number), probably you want to be part of it (the coalition) as early as possible, de Kerchove said in televised remarks to the BBC.

One of those militants with suspected U.K. ties is a masked man seen in videos of the beheadings of two American journalists and a British aid worker. FBI Director James Comey on Thursday said U.S. officials believe they know his identity. Comey did not release the name or nationality of the man dubbed "Jihadi John," who speaks in British-accented English in the videos.

Coalition warplanes continued to bomb oil installations and other facilities in territory controlled by the Islamic State in eastern Syria on Friday, according to Britain-based Syrian Observatory for Human Rights, a Syria monitoring group.

The U.S. military said 10 airstrikes were conducted in Iraq and Syria on Thursday and Friday.

Contributing: Gregory Korte in Washington.