Ahead of his first trip as secretary of state to South America, Rex W. Tillerson warned countries in the Western Hemisphere on Thursday about the dangers of the region’s growing trade with China and Russia.

“China’s offer always comes at a price,” Mr. Tillerson said in a speech at the University of Texas, Austin, where he was once a student. “Latin America does not need new imperial powers that seek only to benefit their own people.”

In wide-ranging remarks, Mr. Tillerson also pledged more help in Mexico’s fight against drug cartels and Colombia’s peace initiative and efforts to cut back on coca production. He also called on both Cuba and Venezuela to embrace democracy, and said that updating the North American Free Trade Agreement and striking other trade deals were a priority.

But his most pointed remarks came in his warning against Russian military sales and trade with China, which has displaced the United States as the largest trading partner for Chile, Argentina, Peru and Brazil.

“Our region must be diligent to guard against faraway powers,” he said in an echo of what Chinese officials say about the United States in Asia.

Later Thursday, Nikki R. Haley, the United States’ ambassador to the United Nations, was also deeply critical of Russia, saying, “Russia is not our friend.”

She touted what she said was the Trump administration’s hard line against Russia, pointing to expanded sanctions and to the decision to send weapons to Ukraine. “In the last year, this administration has been tougher on Russia than any American administration since Ronald Reagan,” she said.

Mr. Tillerson delivered his speech exactly one year after he was confirmed as secretary of state. It was the most confident of his tenure, as he easily fielded students’ questions with great detail and without notes.

Stories have receded about Mr. Tillerson’s troubled relationship with President Trump and of his own imminent departure, a narrative supplied privately by critics in the White House. Indeed, Mr. Tillerson is widely expected to remain in his post at least through the summer, and his relationship with Mr. Trump appears to have stabilized.

Asked in December whether he was enjoying his job, Mr. Tillerson gave a tight smile and offered: “I’m learning to enjoy it.”

He has also been learning to build enjoyable details into his packed travel schedule. On Friday morning, Mr. Tillerson is expected to tour the Metropolitan Cathedral in Mexico City. He will then fly to Nahuel Huapi National Park in Bariloche, Argentina, a vast wilderness on the northern edge of Patagonia, where he plans to ascend an Andean summit on horseback.

In a briefing for reporters, a senior State Department official said the trip to Bariloche was meant to highlight scientific and research exchanges between the two countries. Unmentioned was how much Mr. Tillerson likes horseback riding.

But back at the State Department, morale remains troubled amid serious cutbacks, a grinding reorganization and an exodus of senior diplomats that continued on Thursday.

Thomas A. Shannon Jr., the under secretary of state for political affairs, announced his resignation as the department’s third-highest ranking official. He will serve until his successor is confirmed by the Senate, according to Heather Nauert, the department’s spokeswoman, a process that is likely to take months.

The timing of Mr. Shannon’s announcement was driven by his promise to stay through Mr. Tillerson’s first year, said Steve Goldstein, the department’s under secretary for public affairs. Mr. Goldstein said Mr. Shannon had been hoping to spend more time with his father, following his mother’s death late last year.

In a statement, Mr. Tillerson praised Mr. Shannon’s “devotion to service that has and shall continue to inspire State Department colleagues.” John F. Kelly, the White House chief of staff, released a statement saying the “nation owes him a debt of gratitude.”

Of the five “career ambassadors,” the department’s highest rank, who were in place in January 2017, only one will remain after Mr. Shannon departs. Scores of others who held ranks just beneath Mr. Shannon’s have left.

Mr. Shannon was unusual in that he seemed to thrive during Mr. Tillerson’s first year.

In the administration’s first months, Mr. Tillerson often decided against attending formal functions at the White House and sent Mr. Shannon to serve in his place. When Mr. Trump met with the leaders of Japan, Britain and Canada, Mr. Shannon was by the president’s side.

But within the department, Mr. Shannon was widely rumored to be unhappy with Mr. Tillerson’s decisions to ignore many of the department’s top experts, as well as his failure to identify a cadre of senior leaders or fill vacancies in a large number of ambassadorships. It was often Mr. Shannon who delivered the news to senior diplomats that they were being pushed out of their jobs or would not get the postings they had been promised.

Before South America Trip, Tillerson Warns Against Trade With China

 GARDINER HARRIS 

The New York Times    February. 1, 2018