Developing countries have ended their Monday boycott of United Nations climate change talks in Copenhagen, allowing negotiations to continue toward a new global treaty on responding to global warming, the European Union says.

Maldivian President Mohamed Nasheed addresses Klima Forum 09, the people's climate summit, in Copenhagen on Monday. His small island country is threatened by rising sea levels. (Peter Dejong/Associated Press)EU environment spokesman Andreas Carlgren said informal talks resolved the standoff, which was launched by the G77, a group of developing countries that includes China, Brazil and India.

Formal working groups were cancelled at the 192-country conference after developing states called for the 1997 Kyoto Protocol to be extended past 2012, when it is expected to expire.

Developing countries launched the protest against industrialized ones that were pushing for a new agreement that would jettison key provisions in the Kyoto protocol, which imposes strict penalties on rich nations that don't comply with its emission limits but makes no such demands of developing states. Kyoto also doesn't apply to non-signatories such as the United States.

Rich and poor countries "found a reasonable solution," Carlgren said.

Observers suggested the boycott was an attempt to put pressure on world leaders, many of whom are expected to arrive in Copenhagen on Tuesday.

"They are trying to put the pressure on," said Gustavo Silva-Chavez, a climate change specialist with the Environmental Defence Fund. "They want to make sure that developed countries are not left off the hook."

'We lost some important time today.'—Jim Prentice, Canada's environment minister

But not all developing countries supported the boycott. Mohamed Nasheed, the president of Maldives, told The Associated Press that there was a wide range of opinions in the bloc of developing countries, which includes both impoverished nations and those with fast-growing economies such as China and India.

"There are countries who do not agree to what is happening here, but I don't think we should put all the developing countries together and say there is one unified or one single voice coming out," said Nasheed, whose island country is threatened by rising sea levels.

The cost of cutting greenhouse gas emissions is emerging as another obstacle to a deal in Copenhagen. The developing world is calling for rich countries to pour billions of dollars into a fund they could tap into to help deal with the effects of climate change.

Commonwealth countries agreed to a similar idea at their recent summit in Trinidad — but which nations will pay, and how much funding will be poured into the fight against climate change, have yet to be determined.

Canadian Environment Minister Jim Prentice told reporters on Monday that the decision to boycott negotiations was "not particularly helpful."

"We lost some important time today," he said.

More than 100 world leaders, including Prime Minister Stephen Harper and U.S. President Barack Obama, are expected at the summit for a leaders conference.

The dragging negotiations have spurred protests from environmentalists in the Danish capital, with hundreds of police keeping a close eye on a demonstration that attracted over 3,000 activists.

More than 1,200 people were detained in weekend protests, although almost all were released after questioning.

With files from The Associated Press