Barack Obama, the US president, delayed arrival came on Saturday. He became one of 21 heads of state in attendance, including Hu Jintao and Gloria Arroyo, the Chinese and Philippine presidents respectively, and Paul Rudd, the Australian prime minister.
Lars Loeke Rasmussen, the Danish prime minister, also made a surprise visit to meet with leaders on the sidelines of the summit.
"There was, I'd say, a general consensus of support for what prime minister Rasmussen laid out, which is... 'one agreement, two steps' where Copenhagen would be the first step in a process towards an internationally legally binding agreement," Froman said.
He said Rasmussen told the meeting that "in Copenhagen, he would seek to achieve a politically binding agreement that covered all the major elements of the negotiations, including mitigation, adaptation, technology, and finance."
"I think there was widespread support among the leaders that it was important that Copenhagen be a success, that there would be the achievement of real, concrete progress in Copenhagen with operational impact," he said.
Veronica Pedrosa, Al Jazeera's correspondent at the summit, said a political deal would be backed rather than binding climate change targets.
Also on the talks' agenda was the regime in Myanmar, with the prime minister of the country's secretive and ostracised military junta attending the summit.
The US was seen to be deploying its policy of dialogue with Myanmar to push for democracy and the release of Aung San Suu Kyi, the opposition leader and noble laureate, there.
In a speech in Tokyo last week, Obama said that the US and Myanmar could have better relations if reform took place in the south-east Asian nation, but that sanctions against them would remain until that happens.
"That is how a government in Burma [Myanmar] will be able to respond to the needs of its people," he said.
"That is the path that will bring Burma true security and prosperity."
Obama is the first US president in 40 years to meet a Myanmese leader.
Surin Pitsuwan, Association of Southeast Asian Nations (Asean) secretary-general, told Al Jazeera: "The US is making the two-pronged approach that is dialogue and keeping all other options open - including pressure and sanctions.
"The potential is great. It depends on how we handle this new, more open, however from the US towards Asean nations."
It was announced that the US state of Hawaii will host the 2011 summit, although a final statement from this year's summit has not yet been released, with leaders disagreeing on the final draft.
Economic considerations are expected to dominate that statement. Analysts predict the 21 leaders to agree to maintain economic stimulus packages to fight recessions, and address protectionism - particularly that of the US.
Several Apec leaders have been critical of the imposition of trade restrictions by Washington recently.
Obama joined the grouping later than expected, in order to attend a memorial service for the victims of the Fort Hood shootings in Texas, but attended a dinner with his Asian counterparts on Saturday night.