The United Nations says an additional round of global climate talks is being scheduled for September ahead of the annual ministerial summit at the end of the year.

Diplomats currently meeting in Bonn, Germany, have been struggling to draft a text they can put before ministers at the summit in Poland in December.

At issue are the precise rules countries have to stick to in fulfilling the 2015 Paris climate accord, as well as questions of funding for poor nations and how to close the gap between what governments have pledged to do and what's needed to meet the goal of keeping global warming below 2 degrees Celsius.

The UNFCCC, which oversees the negotiations, said late Wednesday that the additional meeting will be held in Bangkok, Sept. 3-8.