BERLIN -- Officials overseeing a UN-backed fund to help poor countries tackle climate change are meeting in Bahrain, following the recent resignation of its director and a shortfall in contributions from rich nations.

The four-day meeting of the Green Climate Fund's board starting Wednesday will address the gap between $10.2 billion pledged by developed nations for 2015-2018, and the $6.6 billion received.

U.S. President Donald Trump has withheld $2 billion of the $3 billion pledged by his predecessor Barack Obama.

There's also concern about some funding requests. Bahrain wants money to protect its freshwater reserves even as the rich Gulf nation extracts vast amounts of oil and gas that fuel global warming.

The fund's last director, Howard Bamsey, resigned in July after what officials described as a "very difficult and disappointing " meeting.