Achim Steiner speaks in Bodo, Nigeria, during the start of an exercise to clean up pollution in Ogoni land, Nigeria June 2, 2016. REUTERS/Afolabi Sotunde

UNITED NATIONS (Reuters) - United Nations Secretary-General Antonio Guterres on Tuesday named an environmental and politics expert, Achim Steiner of Germany, to head the U.N. Development Programme, replacing former New Zealand Prime Minister Helen Clark, who steps down on Wednesday.

The U.N. agency works in 170 countries and territories to try and wipe out poverty, reduce inequalities and exclusion and promote sustainable development. In 2015 the agency received $4.5 billion in voluntary funding.

The United States was among the top government contributors to the UNDP in 2015, giving $266 million, but the administration of President Donald Trump is pushing cuts to diplomacy and foreign aid.

Steiner is director of the Oxford Martin School at the University of Oxford. From 2006 to 2016 he was U.N. Environment Programme executive director and also the director general of the U.N. office in Nairobi from 2009 and 2011.

U.N. spokesman Stephane Dujarric said Guterres has asked the 193-member General Assembly to confirm Steiner for a four-year term.