U.N. diplomats say Norway's former environment and development minister Erik Solheim has been chosen by Secretary-General Ban Ki-moon to head the U.N. environment agency.

Solheim currently heads the Organization for Economic Cooperation and Development's committee on development assistance. He also serves as special envoy for environment, conflict and disaster for the United Nations Environment Program known as UNEP.

The diplomats, speaking on condition of anonymity ahead of a formal announcement, said Monday that Solheim will succeed Achim Steiner as UNEP's executive director, with the rank of undersecretary-general. Steiner served two four-year terms and had his mandate extended an additional two years until June 2016.

Nairobi-based UNEP calls itself "the leading global environmental authority that sets the global environmental agenda" and advocates for environmental protection.