U.K.'s David Cameron signals support for more airstrikes on ISIS

Prime Minister David Cameron declared Sunday that Britain needs to take a greater role in destroying the Islamic State group in Syria — his most direct signal to date that he will seek to expand his country's role in supporting the United States and its allies.

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In remarks made to NBC News' Meet the Press, Cameron said Britain must do more to fight the group, also known as either ISIS (Islamic State in Iraq and Syria) or ISIL (Islamic State of Iraq and the Levant).

The remarks, which follow a commitment to meet NATO targets on military spending, make plain that Britain now sees the group as an explicit threat to national security.

"We know that we have to defeat ISIL, we have to destroy this caliphate, whether it is in Iraq or in Syria," he said. "That is a key part of defeating this terrorist scourge that we face."

The remarks come only days after Britain's ministry of defence acknowledged that British forces have already conducted airstrikes over Syria — albeit only when embedded with coalition forces. Britain has been carrying out surveillance and air-to-air refueling over Syria and launching attacks on neighbouring Iraq and Defence Secretary Michael Fallon has argued that legislators should expand the mission to Syria.

Cameron has been reaching out to the opposition Labour Party to win support — trying to build a unified national position and avoid another embarrassing defeat on Syria. Labour torpedoed previous efforts to join U.S. attacks on Syria in 2013.

The British leader paired his wish for expanded military action with a promise to persuade young Britons to reject Islamic State and its dictates.

"We've got to defeat the narrative of extremism, even when it's not connected to the violence," Cameron told NBC. "Because it's the narrative that is the jumping-off point for these young people to then go and join this dreadful death cult in Iraq and Syria."

Tackling home-grown extremism

On Monday, Cameron will give a major speech heralding a five-year plan to tackle radicalization and extremism in the U.K. But Downing Street has already released extracts of the speech in advance.

In it, Cameron is expected to warn young Britons tempted to join ISIS that they will become nothing more than "cannon fodder" for the extremists.

He's also expected to call for a renewed drive to promote British values as part of the government's new strategy.