One of the State Department's most experienced negotiators resigned Friday, becoming the latest veteran member of the country's diplomatic corps to leave.

Sources told Foreign Policy that Joshua Black, a chief U.S. sanctions and counterterrorism expert at the United Nations, stepped down from his post due to a growing disillusionment with the Trump administration.

The publication reports Black was opposed to the attitude the administration had taken toward a number of multilateral deals and institutions.

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The president has removed the U.S. from the 2015 Paris climate accords and has disavowed the multination Iran nuclear deal.

Foreign Policy reported Black was unhappy with the way the administration "was tearing down a landmark nuclear deal he had personally participated in building."

The U.S. Mission to the U.N. declined to comment to the publication on reasons why Black resigned.

Sixty percent of top-ranking career diplomats have left the State Department and the number of people looking to join the Foreign Service has decreased, according to a recent McClatchy report.

The U.S. ambassador to Panama resigned last week.

The departures come as the U.S. faces a number of global issues.

Tensions have skyrocketed with North Korea and Iran, and President Trump Donald John TrumpUS reimposes UN sanctions on Iran amid increasing tensions Jeff Flake: Republicans 'should hold the same position' on SCOTUS vacancy as 2016 Trump supporters chant 'Fill that seat' at North Carolina rally MORE's decision to recognize Jerusalem as the capital of Israel has sparked unrest in the Middle East.