MEXICO CITY — The U.S. ambassador to Mexico, Roberta S. Jacobson, plans to leave her post this spring, a move that could further strain a rapidly deteriorating relationship between the two countries at a time of major negotiations on trade, a controversial border wall project and an upcoming presidential election in Mexico.

An experienced diplomat and Latin America expert, Jacobson is the latest of several high-level officials at the State Department to part ways with the Trump administration. In a letter to embassy staffers Thursday, Jacobson did not focus on her personal reasons for her resignation, effective in May. She described it as a “difficult decision” but said it was “the right time to move on to new challenges and adventures.”

Jacobson took up the post in 2016. Her departure was first reported by the New York Times.

As her replacement, the Trump administration is looking to name Edward Whitacre Jr., a former chief executive of General Motors and AT&T, who also has worked with Carlos Slim, Mexico’s richest man, according to U.S. and Mexican officials familiar with the decision. Whitacre’s name was first reported by the Mexican newspaper Reforma. White House officials did not respond to a request for comment.

Whitacre, a Texas native, has been president of the Boy Scouts of America and a board member of ExxonMobil, which probably put him in contact with Secretary of State Rex Tillerson, also a past president of the Boy Scouts and a former Exxon chief executive. A call to Whitacre was not immediately returned.

Whitacre will enter a fraught relationship between the United States and Mexico. Last month, President Trump and President Enrique Peña Nieto held a troubled phone call in which the two disagreed about Trump’s proposed border wall. Peña Nieto called off a planned trip to Washington after the conversation, the second time during Trump’s tenure that such a visit has been canceled. Meanwhile, months of talks to overhaul the North American Free Trade Agreement have yet to yield a resolution.

If the new U.S. ambassador pushes harder on Trump’s favorite themes — including stopping illegal immigration from Central America — the relationship could deteriorate further, according to Mexican analysts.

“This will become a more complicated relationship with the new ambassador,” said Jorge Chabat, a professor at CIDE, a research institution in Mexico City.

Jacobson, who grew up in Englewood Cliffs, N.J., and entered the State Department in 1986, during the Reagan administration, has brought a wealth of Latin America expertise to the position of ambassador. She is widely liked by Mexican officials, who often describe her as trying to preserve the productive relationship that existed during the Obama administration.

“We Mexicans will miss Roberta,” said Rafael Fernández de Castro, director of the Center for U.S.-Mexican Studies at the University of California at San Diego. “She did a wonderful job keeping communication channels open with her Mexican counterparts as President Trump both weakened the State Department and bashed Mexico. She was a blessing when the U.S.-Mexico relationship most needed it.”

Jacobson has spent most of her State Department career in the Western Hemisphere section, including as assistant secretary of state for Western Hemisphere affairs and several other high-level positions.

State Department Undersecretary Steven I. Goldstein confirmed that Jacobson has announced her intention to retire and had told Tillerson when he was in Mexico last month. “We are grateful to her, and we are sorry to see her go,” Goldstein said.

Many observers expected Trump would replace Jacobson at some point and bring in someone who more closely shares his views.

Other Latin America experts, such as the U.S. ambassador to Panama, John D. Feeley, also have announced their intention to leave their posts.

Jacobson mostly highlighted the work of her subordinates.

“We have ensured criminals who prey on the most vulnerable faced justice, that women and children trafficked like merchandise were freed, that migrants knew their rights, that dangerous drugs were removed from the marketplace and reach of our children, that democracy was strengthened, and the judicial playing field leveled where we could,” she wrote. “We have worked for American and Mexican prosperity, promoted exports from the United States and literally hundreds of U.S. companies, and help generate good jobs that bring with them dignity.”

Anne Gearan in Washington and Gabriela Martinez in Mexico City contributed to this report.