The State Department said Thursday that it is not worried about a recent exodus of several senior officials that has led to renewed concerns over plummeting morale in the diplomatic corps under Trump.

Heather Nauert, a spokeswoman for the department, told reporters at a press briefing that the administration still has a "tremendous number of qualified, good people" continuing the work of top officials, who have departed.

"You all may not know their names. It doesn’t mean that they don’t exist and that they’re not excellent at their jobs," she said.

ADVERTISEMENT

Nauert's comments came hours after Roberta Jacobson, the U.S. ambassador to Mexico, announced that she will step down from her post in May to pursue "other opportunities."

Jacobson's planned resignation is the latest in a series of departures at the State Department, particularly among its diplomatic ranks.

Joseph Yun, the Trump administration's point person on North Korea, announced this week that he would retire after more than three decades in the U.S. Foreign Service.

Yun's retirement followed that of Thomas Shannon, the under secretary of State for political affairs and one of the most senior officials to remain in his job after President Trump Donald John TrumpBiden leads Trump by 36 points nationally among Latinos: poll Trump dismisses climate change role in fires, says Newsom needs to manage forest better Jimmy Kimmel hits Trump for rallies while hosting Emmy Awards MORE took office last year.

One of the most stunning resignations to hit the State Department's diplomatic ranks in recent weeks was that of John Feeley, the U.S. ambassador to Panama, who declared in a resignation letter that he could not serve under Trump.

“As a junior foreign service officer, I signed an oath to serve faithfully the president and his administration in an apolitical fashion, even when I might not agree with certain policies,” Feeley said, according to a report by Reuters.

"My instructors made clear that if I believed I could not do that, I would be honor bound to resign," he continued. "That time has come."

Nauert pointed out on Thursday that many of the officials who have resigned had reached retirement age and had been serving in the State Department for decades. She talked about a "fundamental belief" within the department that younger people should be promoted to fill the positions of more senior officials.

"We look to the future generations of people who are younger in this department to be able to bring them up through the ranks and take over these positions," she said. "Do you want somebody around forever?"

Still, Trump has not yet nominated replacements for Shannon, Feeley, Yun or Jacobson, and those absences are likely to be felt. Washington's relations with Mexico are on the rocks amid Trump's threats to pull the U.S. out of the North American Free Trade Agreement and vow to build a wall along the southern border. And the U.S. is still leading an international pressure campaign against North Korea in an effort to force it to abandon its nuclear program.

Nauert insisted Thursday that there are people in line for the vacant posts.

"There are people in mind and in line for those types of positions," she said. "Perhaps you’ve just not heard about it yet."

--Updated at 8:44 p.m.