COPENHAGEN, Denmark - The atmosphere at the U.N. climate conference grew more tense and divisive after talks were suspended for most of yesterday's session, a sign of the developing nations' deep distrust of the promises by industrial countries to cut greenhouse-gas emissions.

With only days left before the conference closes Friday, some leaders said they would come early to try to salvage the negotiations.

The wrangle over emission reductions froze a timetable for government ministers to negotiate a host of complex issues. Though procedural in nature, the Africa-led suspension went to the core of suspicions by poor countries that wealthier ones were trying to soften their commitments and evade penalties for missing their emissions targets.

Talks were halted most of the day, resuming only after conference president Connie Hedegaard of Denmark assured developing countries she was not trying to kill the Kyoto Protocol, the 1997 document that requires industrial nations to cut emissions and imposes penalties if they fail to do so. Kyoto makes no demands on developing countries.

Among the issues put on hold because of the suspension: whether China will be asked to make sacrifices similar to those demanded of the United States and other rich nations; whether China will open its carbon books to outside inspection; how to ensure every country counts its carbon emissions the same way; and how to raise a steady flow of money for poor countries to combat climate-linked economic disruptions such as rising seas, drought, and floods.

The delay came just days before President Obama, Chinese Premier Wen Jiabao, and more than 110 other world leaders were scheduled to arrive to cap two years of negotiations on an agreement to succeed Kyoto.

2015 or 2030?

After the stalemate ended yesterday, former Vice President Al Gore told the conference that new data suggested a 75 percent chance the entire Arctic polar ice cap may disappear in the summertime as soon as around 2015 to 2017. Gore, who won a Nobel Peace Prize for his work on climate change, joined the foreign ministers of Norway and Denmark in presenting two new reports on melting Arctic ice.

But others questioned the "aggressive" projection. "It's possible but not likely," said Mark Serreze, a scientist at the U.S. National Snow and Ice Data Center in Boulder, Colo. "We're sticking with [the year] 2030."

Outside the hall where talks were going on, police detained up to 200 people after protesters set fire to street barricades in a downtown neighborhood. Protesters hurled fire bombs at riot officers who responded with tear gas. There were no immediate reports of injuries.

'Physics isn't politics'

The world leaders are seeking a political agreement in Copenhagen rather than a legally binding treaty. Still, the goal is to nail down individual targets on emissions cuts and financing for developing countries in a deal that can be turned into a binding pact next year. The talks are aimed at extending the Kyoto pact for at least five more years.

Mohammed Nashid, president of archipelago nation of the Maldives, helped resolve the deadlock yesterday with an impassioned speech to the African nations to return to the talks.

Outside the conference, he voiced his frustration. "In all political agreements, you have to be prepared to negotiate," he said. ". . . But physics isn't politics. On climate change, there are things on which we cannot negotiate."

On the sidelines of the talks, U.S. Energy Secretary Steven Chu announced a program drawing funds from international partners to spend $350 million over five years to give developing nations solar-energy systems and other clean-energy technologies to poor countries.

The U.S. cost would be $85 million. The International Energy Agency said that $8.3 trillion would be spent on new energy in the next 20 years but that the entire amount could be recovered in cheaper energy and in energy efficiency.