BONN, Germany — Differences emerged Friday at the outset of the first U.N. climate conference since the disappointing Copenhagen climate summit, as delegates from 175 countries began mapping out a path toward a hoped-for global warming deal by the end of this year.

The failure of the summit in December in the Danish capital to agree on the architecture of a new climate treaty hung heavily over negotiators concerned that the process begun more than two years ago was badly damaged, and uncertain about how to go forward.

The three-day U.N. conference is meant to set a program of meetings leading up to the next major conference in Cancun, Mexico, and decide whether Cancun should aim for a legally binding agreement or an outline that can be completed over the next year.

Few delegates believed a full treaty can be completed this year, and probably will wait until the end of 2011.

The meeting ran into immediate discord over how to regard the only document to come out of the contentious summit, the three-page Copenhagen Accord brokered by President Barack Obama with China and a few major developing countries in a hectic round of consultations on the final day.

African nations said the Copenhagen Accord was done by "a selected few," and any further attempt to bypass the majority "will obstruct the process."

"To repair this damaged process we must learn the lessons from Copenhagen," said Congolese delegate Nsisli Tosi Bibande Mpanu Mpanu, speaking for the Africans. "They broke the trust that is necessary for any partnership," he said.

Abdullah M. Alsaidi of Yemen, representing some 135 developing countries, said negotiations must be centered in the two committees under the U.N. talks. Those committees have been struggling with the draft of a treaty with little success, and it was the prospect of ending Copenhagen with no agreement that prompted Obama to seek a less ambitious deal.

The U.S. delegation did not immediately address the meeting.

But Australian delegate Louis Hand, speaking for a group of nations that includes the U.S., said the Copenhagen agreement gave "vital political direction" to the negotiations and was "a package of action" that provided a breakthrough on one of the key elements of an agreement — financing.

The accord called for richer nations to finance a $10 billion-a-year, three-year program to fund poorer nations' projects to deal with drought and other impacts of climate change, and to develop clean energy. It also set a goal of mobilizing $100 billion a year by 2020, but it did not say how those funds should be raised or distributed.

The document sidestepped issues that have stymied the talks from the start — setting binding targets for both industrial and developing countries for controlling greenhouse gases blamed for causing the Earth's average temperatures to rise. Instead, it opted for voluntary emission controls which could be internationally monitored.

Some 120 nations have affirmed support for the accord. But the U.N. climate process operates by consensus, meaning at least tacit approval by all 194 participating parties.

"The parties are still talking past each other," said Annie Petsonk, of the Environmental Defense Fund after the opening session. "If that continues we may see more energy going into parallel processes," she said, referring to informal meetings of smaller groups outside the U.N. framework.

Mexico, which will chair the Cancun conference, has been holding private consultations to establish what will be within reach at the crucial end-of-year conference.

"Progress requires adjustment and modernization" in the negotiating process, said Mexico's chief negotiator Fernando Tudela.

"Gone is the time for reiterating positions," said Mexican ambassador Fernando Tudela.