The head of the U.S. Agency for International Development will step down next month from the nation’s premier arm for humanitarian aid amid a snowballing pandemic.

Mark Green said his resignation, submitted to President Trump in a letter Sunday, does not stem from any dissatisfaction with the administration’s response to the coronavirus outbreak.

“They’re not related at all,” Green said in a phone interview about his departure from USAID, where he has been the administrator for the past 2½ years.

Green is expected to be replaced, at least temporarily, by Bonnie Glick, the deputy administrator. But his departure leaves the administration with one less experienced hand to help coordinate a worldwide response to the most serious crisis to confront the Trump White House. That could have broader implications if the hot spot shifts from Europe, where USAID is less active, to regions where it is more entrenched, such as Africa and Southeast Asia.

Early this month, USAID announced a $37 million donation to help groups such as the World Health Organization cope with the outbreak. In its latest budget request, the Trump administration has proposed cutting funding for global health programs by more than $3 billion. But Congress is unlikely to go along with that, given broad bipartisan support for foreign aid meted out by USAID and the State Department.

USAID is an independent agency that has the primary authority to administer aid for civilian, humanitarian and development programs. It recently pulled together a team to coordinate its response to the coronavirus and has sent protective equipment and money to several countries.

Green expressed confidence that USAID is prepared to continue helping countries hit hard by the pandemic.

Green, whose last day will be April 10, would not discuss his next move, saying he will elaborate in coming days. But two people familiar with Green and his plans said he will become president of Arizona State University’s McCain Institute for International Leadership.

The McCain Institute, a pro-democracy think tank, is named after the late senator John McCain (R-Ariz.), whom Trump has frequently criticized.

Green, a former Republican congressman from Wisconsin, established a strong rapport with many in the administration. He traveled overseas with first lady Melania Trump and accompanied Ivanka Trump, the president’s daughter, on several trips as she promoted the Women’s Global Development and Prosperity Initiative.

In his resignation letter to Trump, Green cited his work with Ivanka Trump as well as several other signature foreign policy initiatives. Among them were providing aid to alleviate man-made disasters such as the economic collapse in Venezuela and diverting U.S. aid to faith-based groups including Christians persecuted by the Islamic State militants in Iraq, a pet project of Vice President Pence’s.

During Green’s tenure, USAID responded to traditional humanitarian crises including earthquakes in Mexico, a hurricane in the Bahamas and a plague of locusts in East Africa. But natural disasters are becoming a smaller part of the agency’s portfolio.

“We still have those,” Green said. “But increasingly, these human disasters are man-made, ­regime-driven, a fallout from the flight from tyranny. That has caused us to rethink how we do our work, delivering humanitarian assistance in settings that are anything but secure.”

Among lawmakers and groups concerned about international development and humanitarian aid, Green is best known for a transformational approach he calls the “journey to self-reliance” so countries would need less humanitarian aid in the future.

“We continue to be far and away the largest humanitarian donor in the world. But we do need other countries to do more,” he said. “Not because I’m arguing we should do less. But more because the needs are huge.”

Green’s approach won him fans among lawmakers from both parties, and from aid groups.

“Mark Green’s tenure at the helm of USAID has been truly transformational when it comes to delivering results for the American people,” said Liz Schrayer, president of the U.S. Global Leadership Coalition. “He modernized how the agency is organized, scaled up leverage with the private sector, and focused our development agenda on self-reliance — all while never losing sight of our nation’s humanitarian values.”

Green, who first held elective office when he joined the Wisconsin State Assembly in 1993, said he does not intend to seek public office again.

“I cannot see myself returning to the arena,” he said of what he characterized as “interesting political times.”

“Every now and then I send an email to former colleagues saying, ‘It’s kind of fun being in the cheap seats.’ ”