Prime Minister David Cameron said on Sunday he wants Britain to do more to help defeat the self-declared Islamic State in Syria as part of what he described as a “full-spectrum response” to the radical Islamist group.

“We have to destroy this caliphate, whether it is in Iraq or in Syria,” Cameron told the American news program Meet the Press. “That is a key part of defeating this terrorist scourge that we face.”

Although British jets have been striking Islamic State targets in Iraq with the permission of the central government there, the United Kingdom shied away from carrying out attacks in Syria in 2013 when the opposition Labour Party demanded a United Nations Security Council resolution before authorizing military intervention.

Cameron recognized on Sunday he would need lawmakers’ support before Britain could conduct strikes in Syria. “I’ll always have to take my Parliament with me,” he said.

Unlike America’s NATO allies, the Islamic State does not respect the border between Iraq and Syria. Drawing on Sunni resentment with the minority regime of Bashar al-Assad in Syria and the Shia-dominated government in Iraq, it has been able to conquer areas stretching from near Syria’s Aleppo in the west to Mosul in northern Iraq and south to Fallujah, seventy kilometers west of Baghdad.

Britain’s Royal Air Force has flown daily sorties against Islamic State targets in Iraq for the past year but only carries out 4 percent of total strikes against 92 percent for the Americans.

In Syria, British forces are confined to providing support for American attacks in the form of air refueling, logistics and surveillance, Cameron said.

The Islamic State’s military successes have inspired hundreds of Britons to join its campaign in Iraq and Syria. The group has also inspired would-be jihadists in the West. In the last year, lone radicalized Muslims have staged attacks in Copenhagen, Ottawa and Sydney.

Last month, a gunman radicalized by Islamists killed 38 tourists, thirty of them British, at a resort in Tunisia.

Opposition parties in the United Kingdom nevertheless hesitate to involve the country in Syria’s civil war where the Islamic State is one of the groups fighting Assad’s regime.

When it emerged last week that some British pilots had been embedded with American and Canadian forces and participated in strikes over Syria, the Liberal Democrats — who ruled in coalition with Cameron’s Conservatives until earlier this year — spoke of “a breach of trust with the British people.”

Labour is still smarting over its support for the American-led invasion of Iraq in 2003, now widely seen in Britain as a mistake. An antiwar candidate, Jeremy Corbyn, is second in the race to become the next party leader.

Cameron could go to war with the support of his Conservatives alone. But they only have a twelve-seat majority after winning 36 percent of the votes in May’s election; a thin mandate for involving Britain in a civil war where it would rather see neither the Assad regime nor the Islamist opposition win.