UPDATE 1-U.N. climate deal retreats as Bonn talks end

* Countries mull new text, seen larger than needs to be

* Backtracking, insertions, U.S. blamed for slow progress

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By Nina Chestney

BONN, Aug 6 (Reuters) - U.N. climate talks have moved backward rather than forward toward a hoped-for deal later this year as nations make slow progress on pledges to cut greenhouse gas emissions and add more proposals to the working document.

As talks in Bonn on a new climate treaty draw to an end on Friday, the frustration of delegates with the process this week is clearly felt, and a deal in Mexico this year seems unlikely.

This week's meeting is the penultimate before a meeting set for the end of November in Cancun, Mexico.

"I came to Bonn hopeful of a deal in Cancun, but at this point I am very concerned as I have seen some countries walking back from progress made in Copenhagen," said Jonathan Pershing, the U.S. deputy special climate envoy.