LE BOURGET, France — Negotiators released a new, shorter draft of an international accord to fight global warming Wednesday — and it leaves key issues unresolved just two days before high-stakes talks in Paris are scheduled to end.

U.S. Secretary of State John Kerry challenged diplomats to reach agreement by Friday’s self-imposed deadline, promising American funding for countries hardest hit by the rising seas and extreme weather that scientists attribute to man-made emissions that are changing the world’s climate.

The new draft document released by the U.N. climate agency is 29 pages, down from a 48-page version released Saturday.