HALIFAX, Nova Scotia (AP) — British Prime Minister David Cameron steps into a potential hornets' nest of trans-Atlantic conflict when he makes his global debut this week at the G-20 summit in Canada — with tensions over Afghanistan, Europe's debt crisis and the BP oil spill gaining in intensity.

Cameron, who took office just over a month ago, will likely seek to smooth London's "special relationship" with Washington while standing firm on British interests as he strives to hone credentials as an international statesman.

In a sign that he doesn't intend to let his position as the new kid on the block hold him back, Cameron used an opinion piece in Canada's Globe and Mail newspaper on Thursday to chastise his fellow leaders over summits that "fail to live up to the hype and to the promises made."

"Good intentions are shared in productive talks. Then somehow those intentions seem rarely to come to fruition in real, tangible global action," Cameron wrote. "And when we meet again a year later, we find things haven't really moved on."

But he faces a tricky task in forcing concrete action.

President Barack Obama, dealing with crises on multiple fronts and fighting perceptions of weak leadership, has his own interest in trying to reassert authority at the high-profile summit of world leaders held over three days in Huntsville, Ontario, and Toronto.

Obama and Cameron hold a bilateral meeting on Saturday, the first time the two men have met face-to-face since Cameron took office at the helm of a coalition government made up of his right-leaning Conservative Party and the left-leaning Liberal Democrats.

On a promising note, the pair appears to have quickly established a stronger rapport than the American president had with Cameron's predecessor, Gordon Brown.

"There's a better personal chemistry between Obama and Cameron than Obama and Brown that may be helpful to the relations," said Monument Securities economist Stephen Lewis.

But as Obama's promise to find out "whose ass to kick" over the BP oil spill rings in British ears, Cameron spokesman Steve Field said the prime minister will be stressing the need for clarity on the costs facing BP. Its financial health is important to millions of Britons who hold BP stock in investment portfolios and pension plans.

Cameron has said BP is prepared to meet its obligations to fund the clean up and compensate those whose businesses have been blighted by the spill, but he also wants to ensure the company remains viable.

Afghanistan is also likely to be high on the agenda. Britain is the second-largest contributor of international troops behind the U.S., but Cameron has said he doesn't want British soldiers to stay "a day longer than necessary," a comment analysts have interpreted as signaling his desire for a winding down of Britain's role there.

Speaking to reporters aboard the plane to Halifax, where Cameron stopped on his way to the summit, the prime minister said his country was paying a "heavy price" for its involvement in Afghanistan, sending condolences to the families of four soldiers killed in a vehicle accident in southern Helmand province Wednesday.

Cameron said that Britain's leaders have to keep asking themselves: "'Are we doing the right thing by conducting this counterinsurgency operation?" but insisted that Britain had to keep to its commitments.

"We would be in a worse situation if we were to just change track now, pull our forces out and to see a country that is seeing a bit more stability track backward into instability and support for terror," he said.

Among the wider G-20, Cameron will be faced with a widening trans-Atlantic rift over how best to deal with Europe's economic crisis — with Washington advocating continued stimulus to keep growth on track and big European powers arguing that the most urgent priority is reining in massive deficits.

Britain's implementation this week of a harsh emergency budget — an austerity package whose effects the government says could be felt for a generation — alarmed Washington, as did similar belt-tightening programs announced in Germany and France.

Obama went so far as to write a letter to world leaders urging them not to implement excessive spending cuts — warning such measures to imperil the global recovery.

But Cameron played down any divisions, acknowledging that the British, French and German levies "won't necessarily be for everyone."

"This weekend isn't about a row over fiscal policy," he told traveling reporters. "We all agree about the need for fiscal consolidation. For me, this G-20 is about putting the world economy on an irreversible path to recovery."

Cameron may also try to create some distance between Britain and continental Europe as he pushes for stronger ties with fast-growing emerging economies like China and India.

Unlike the Labour Party under first Tony Blair and then Gordon Brown, Cameron is not keen on ceding greater power to the European Union. He caused some consternation during the election campaign when he withdrew Conservative members from the main center-right grouping in the European Parliament in favor of an anti-federalist bloc.

His Foreign Secretary William Hague has also expressed a desire for "new beginnings" and closer ties with fast growing economic powers in Asia, the Gulf and Latin America.

How successful Cameron is remains to be seen.

"U.K. governments usually take office with great confidence that they can reassert or redefine Britain's place in the world," think tank Chatham House said in a report after his election. "These hopes are often dashed by their time in power ... sticking to a coherent strategy will be tough in an age of uncertainty."

Cameron was making a brief stopover in Halifax Thursday to visit the Royal Navy's flagship Ark Royal aircraft carrier, which is currently berthed in the Canadian port as part of centenary celebrations of the Canadian Navy.