By Gerard Wynn

BONN, Germany, May 31

UN climate talks opened on Monday, exposing familiar rifts between rich and poor countries which delegates said were likely to delay a re-start of formal negotiations.

The 185-nation Bonn conference, which will run until June 11, is the biggest international meeting on climate change since a summit last December in Copenhagen failed to agree a new pact.

Several countries said they could not give a green light to formal negotiations on a new text published in mid-May and which outlines a huge range of options for fighting climate change.

The Copenhagen summit last year struggled to overcome suspicion on how to share global effort to curb greenhouse gases under a new deal to succeed the Kyoto Protocol after 2012.

On Monday differences re-emerged when a clutch of Latin American countries said they could not start negotiations on the new text.

The United States said it did not think the new text was intended as a basis for negotiations and South Africa said the document put too much burden on developing countries.

The Latin American group including Bolivia, Venezuela and Cuba said on Monday that the new text placed too much emphasis on the Copenhagen accord, which they opposed in December.

"The chair has prioritised the Copenhagen Accord," said Rene Gonzalo Orellana Halkyer, a member of the Bolivian delegation, speaking on the sidelines of the talks in Bonn.

Bolivia also wanted tougher targets, for example to return atmospheric greenhouse gases to a level far below where they are already, he added.

The Copenhagen Accord seeks to limit a rise in average world temperatures to below 2 degrees Celsius (3.6 F) over pre-industrial times but does not spell out how.

Margaret Mukahanana-Sangarwe of Zimbabwe chairs the U.N. talks on forging agreement on global action and is expected to release a revised version next weekend, delegates said.

First Step

The United States said it believed Mukahanana-Sangarwe's text was not intended to be the basis of negotiations.

"Our view is that the text is Margaret's effort to elicit views so she can develop a formal negotiating text," said Jonathan Pershing, head of the U.S. delegation. "It's a constructive next step."

It remained to be seen whether countries can start negotiations on a revised text in the next two weeks, he told Reuters.

The head of the South African delegation, Alf Wills, said the new text focused too far on cuts in greenhouse gas emissions by developing countries.

"It's completely unbalanced in that respect," he said.

However Karsten Sach, head of Germany's delegation, said: "We think it is a basis for negotiation."

An additional, specific gap to be addressed at the Bonn talks was whether or not developed countries should be allowed to exclude from their national greenhouse gases carbon emissions from chopping trees to produce renewable energy.

That rule, allowed under the existing Kyoto Protocol, would represent "fraudulent accounting", said the head of Papua New Guinea's delegation, Kevin Conrad.