LIMA, Peru - Already well into overtime, U.N. climate talks reached a standstill Saturday as developing countries rejected a draft deal they said would allow rich countries to shirk their responsibilities to fight global warming and pay for its impacts.

The main goal for the two-week session in Lima was relatively modest: Reach agreement on what information should go into the pledges that countries submit for a global climate pact expected to be adopted next year in Paris. But even that became complicated as several developing nations rejected a draft decision they said blurred the distinction between what rich and poor countries can be expected to do.

"We have deadlock," Chinese negotiator Liu Zhenmin told the conference, siding with Malaysia and other developing countries that rejected the draft.

U.S. representative Todd Stern said he was open to tweaking the language, but warned against lengthy negotiations, noting that the conference had already passed its scheduled Friday close.

"Failing to produce the decision before us will be seen as a serious breakdown," which could put the Paris agreement and the entire U.N. process at risk, Stern said.

The momentum from last month's U.S.-China deal on emissions targets faded quickly in Lima as rifts reopened over who should do what to fight global warming. Developed countries want the pledges to focus on emissions cuts, while developing nations also want to see commitments of financial support. Some small island states at risk of being flooded by rising seas also complained the draft made no mention of a "loss and damage" mechanism agreed upon in last year's talks in Poland.

"We need a permanent arrangement to help the poorest of the world," said Ian Fry, negotiator for the Pacific Island nation of Tuvalu.

Though negotiating tactics always play a role, virtually all disputes in the U.N. talks reflect the wider issue of how to divide the burden of fixing the planetary warming that scientists say results from human activity, primarily the burning of oil, coal, and natural gas. Historically, Western nations are the biggest emitters. Currently, most CO2 emissions are coming from developing countries as they grow their economies and lift millions of people out of poverty.