* COP28 climate summit set to run into overtime

* Draft deal drops call to 'phase out' fossil fuels

* EU, US, islands urge oil and gas exit; OPEC opposes

DUBAI, Dec 12 (Reuters) - The COP28 climate summit was hurtling towards overtime early on Tuesday, with negotiators awaiting a new draft deal after many countries criticised a previous version as too weak because it omitted a "phase-out" of fossil fuels.

Countries gathered at the Dubai summit are attempting to agree on a global plan of action to limit climate change fast enough to avert more disastrous flooding, fatal heat and irreversible changes to the world's ecosystems.

A draft of a final deal, published on Monday by the United Arab Emirates, which holds the presidency of the summit, suggested eight options countries "could" take to cut emissions.

One was "reducing both consumption and production of fossil fuels, in a just, orderly and equitable manner so as to achieve net zero by, before, or around 2050".

That would be the first time in history that a U.N. climate summit has mentioned reducing use of all "fossil fuels".

But the move fell short of the "phase-out" of coal, oil and gas demanded by many nations, or the emphasis on cutting their use this decade, which scientists say is necessary to avoid climate change escalating.

Negotiators were waiting for a new text on Tuesday, when the conference was set to close at 0700 GMT, although delegates said the deadline was no longer feasible. COP summits rarely finish on schedule.

The draft was criticised as too weak by participants such as Australia, Canada, Chile, the European Union, Norway and the United States, among the 100-strong group demanding a firm commitment to wean the world off coal, oil and gas.

Greenhouse gas emissions from burning fossil fuels are the main cause of climate change.

"The vast majority of countries want a stronger text - phase down with a view to a long-term phase-out, or transition away from fossil fuels," Norwegian Foreign Minister Espen Barth Eide told Reuters.

Brazil wants a stronger text on ditching fossil fuels, but one that makes clear rich and poor nations could do so in different timeframes, Environment Minister Marina Silva said.

"One of the shortcomings is it does not establish efforts to phase out fossil fuels," Silva told reporters about the draft deal.

Representatives of small island nations said they would not approve a deal that was a "death warrant" for vulnerable countries hit hardest by rising sea levels.

"We will not go silently to our watery graves," said John Silk, the head of the Marshall Islands' delegation.

SAUDI PRESSURE

Sources familiar with the discussions said the United Arab Emirates' COP28 President Sultan al-Jaber had faced pressure from Saudi Arabia, de facto leader of the OPEC oil producers' group to which UAE belongs, to drop any mention of fossil fuels from the text - which he did not do.

Saudi Arabia's government did not respond to requests for comment on Tuesday. A COP28 negotiator for the country declined to comment on the text on Monday night.

In a Dec. 6 letter seen by Reuters, OPEC Secretary General Haitham Al Ghais urged members to reject any COP28 deal that targeted fossil fuels.

Negotiators and observers in the COP28 talks told Reuters that while Saudi Arabia has been the strongest opponent, other OPEC and OPEC+ members, including Iran, Iraq and Russia, have resisted attempts to insert a fossil fuel phase-out into the deal.

Deals at U.N. climate summits must be passed by consensus among the nearly 200 countries present. Then it is up to individual countries to deliver the globally agreed deal, through national policies and investments.

For oil-producing nations, a global deal at COP28 to ditch fossil fuels could signal a political willingness by other nations to slash their use of the lucrative products on which fuel-producing economies rely.

"Kuwait works according to a policy based on preserving the sources of petroleum wealth and their optimal exploitation and development," Oil Minister Saad Al Barrak told the 12th Arab Energy Conference in Doha on Monday.

Despite the rapid growth of renewable energy, fossil fuels still produce about 80% of the world's energy.

It was unclear if China, the world's top greenhouse gas emitter, supported the draft.

Sources familiar with a meeting of COP28 negotiators in the early hours of Tuesday said Beijing had resisted a section of the text which said the world's greenhouse gas emissions must peak before 2025.

China has committed to bring its climate-warming carbon dioxide emissions to a peak before 2030, although experts predict the goal will be met earlier.

Indian environment minister Bhupender Yadav also declined to comment on the latest draft deal.

EU climate commissioner Wopke Hoekstra said the draft deal was "disappointing" and the bloc would negotiate into overtime for a stronger text. "We will talk as long as necessary," Hoekstra told reporters. (Reporting by Valerie Volcovici, Jake Spring, Kate Abnett, David Stanway, Gloria Dickie, Sarah McFarlane; Writing by Kate Abnett; Editing by Elizabeth Piper and Clarence Fernandez)