Delegates to a UN climate conference have agreed to formalize rules to operate a fund that will assist developing countries that are particularly vulnerable to the adverse effects of climate change.

The deal came on Thursday, day 1 of COP28 in Dubai, the United Arab Emirates. The creation of the "loss and damage" fund was agreed upon at COP27 last year.

The fund will be hosted by the World Bank for the first four years of its launch. Developed nations and others will commit money to it on a voluntary basis.

The UAE, Germany, Japan and other countries have so far pledged a total of 420 million dollars to the fund.

The UAE's Industry and Advanced Technology Minister Sultan Ahmed Al Jaber, who serves as president of COP28, told a news conference that the agreement is historic. He said it is unprecedented to achieve such a significant milestone on the first day of a COP.

Two-day summit-level meetings will begin at COP28 on Friday, with Japanese Prime Minister Kishida Fumio and other world leaders scheduled to give speeches.

The conference also includes an opportunity to see how much progress countries and other stakeholders have collectively made to meet the goals of the Paris Agreement. The assessment, known as the "global stocktake," happens once every five years.