DUBAI, Dec 12 (Reuters) - Negotiations have formally entered high-stress mode.

With just hours to go before the COP28 climate summit is scheduled to end, nearly 200 countries remain sharply divided on the toughest issue: what to do about fossil fuels.

The COP28 President Sultan Al Jaber had an urgent tone on Monday night when he asked negotiators to find consensus, and quickly: "Let's not rest until we get this done."

The latest draft deal, released by the UAE host on Monday, touched off a firestorm of criticism.

It listed options nations could take to slash emissions, but "phasing out" oil and gas wasn't among them - an apparent concession to OPEC nations that have lobbied against such language from start.

Big powers like the U.S. and the EU that have pushed for a phase out were not pleased, and tiny ones like Samoa and the Marshall Islands were calling it a death sentence.

The best guess for what to expect on Tuesday is for a new draft of a potential final deal to drop sometime, perhaps in the morning. Then, if all goes well, it will be adopted.

More likely: divisions will remain, and the summit will go into overtime, a pattern that has become routine for COPs. (Reporting by Richard Valdmanis, Editing by Marguerita Choy)