Mr. Guterres has had only a brief meeting with Mr. Trump in the White House and is still waiting for Mr. Trump to set a date for a lunch invitation.

That is unusual. Six months into the job, it is customary for the head of the world body to have had a more substantive meeting with the president of the United States, the organization’s largest funder and most influential member. (The United States pays 22 percent of the organization’s general budget and 28 percent of its peacekeeping budget, according to a formula negotiated with other countries.)

Mr. Guterres told reporters on Tuesday that he would meet soon with members of Congress, including Speaker Paul D. Ryan. Lawmakers are arguably an even more important constituency than the president for Mr. Guterres to win over; key congressional committee members control the purse strings, and can help him stave off the deep funding cuts the Trump administration is proposing for international organizations.

After the news conference, aides said Mr. Guterres would travel to Washington next week.

The secretary general has been critical of several Trump administration moves. He said in February that its efforts to bar the citizens of seven majority-Muslim countries from entering the United States were both counterproductive and a violation of “our basic principles.” And he said in his remarks on Tuesday that the world’s rich countries should accept for resettlement many more refugees from the world’s war zones, including Syria.

In April, he reacted to the United States’ withdrawal of funding for the United Nations’ population agency by warning of “devastating effects on the health of vulnerable women and girls and their families around the world.”