The leader of Britain's Conservatives said Friday that if elected he would be far more cautious than his predecessors in deciding to deploy British troops abroad.

Britain's military has been strained by the wars in Iraq and Afghanistan, interventions that also have deeply divided public opinion. Britain's Tories supported both conflicts, but party leader David Cameron said more thought is needed for such operations in the future.The Conservatives are widely expected to take power in an election that must be held by June. They hold double-digit leads in the polls.

"We've got to think through much more carefully whether Britain should get involved in a foreign conflict, and if so, how to cope with the consequences," Cameron said in a speech before Chatham House, a foreign affairs think tank in London.

Cameron didn't say what he would do with the more than 10,000 British soldiers currently serving in Afghanistan, although he's previously been quoted as saying that a reduction in their number is "pretty unlikely."

His speech comes as Kim Howells, a former minister with the governing Labour Party, was quoted as saying that Britain needs to scale back its role on the world stage.

In an interview with The Independent newspaper published Friday, Howells said that the international community always looked to the United States and Britain to police the world's trouble spots — and that that needed to change.

"When there have been big problems — Sierra Leone, Bosnia — it's our troops who have been at the very sharp end, in places of great danger. It can't continue," he was quoted as saying.

A surge in British casualties in Afghanistan has shaken the public's patience with its commitment there, now stretching into its ninth year. Complaints from lawmakers, retired generals, and military families that British forces have been sent into the field without proper equipment or air support have become increasingly pointed as the fighting in Afghanistan intensifies.

Britain maintains the second-largest foreign contingent in Afghanistan after the United States. It has smaller garrisons elsewhere, with troops stationed in Cyprus, Gibraltar, Germany and the Falkland Islands, among other places. British forces pulled out of Iraq last year.

In an interview with BBC radio, Cameron's national security adviser, Pauline Neville-Jones, said Britain was overtaxing its resources.

"We need to approach these things differently, because exercising power in the world in that way is unsustainable," she said, adding that while Britain still had a contribution to make, "we are not a superpower."