A senior Trump administration official tested positive for the coronavirus after a recent trip to Britain, Hungary and France, raising concerns about the spread of the virus to high-level officials across the Atlantic, according to four U.S. and foreign officials familiar with the situation.

Peter Berkowitz, the director of policy planning at the State Department, met with senior officials at 10 Downing Street and the Foreign Office in London, and with officials in Budapest and Paris earlier this month. One official said that Berkowitz’s mask-wearing and social distancing practices were lax during the trip and that U.S. embassy staff in Europe expressed some concerns before the trip about him traveling during the pandemic.

A State Department spokeswoman denied that Berkowitz’s mask usage was insufficient and said precautions were taken. She, like others, spoke on the condition of anonymity to discuss individual coronavirus infections.

Following Berkowitz’s visit to London, British officials have started being more selective about approval of American delegations, officials said. They have postponed an upcoming trip by Elliott Abrams, the U.S. special envoy for Iran and Venezuela, officials said.

The British Embassy in Washington declined to comment.

The State Department spokeswoman said Berkowitz “consistently followed the mask-wearing protocol demonstrated by his counterparts from the host government. As Secretary [Mike] Pompeo has said, we take the threat posed by COVID-19 very seriously, and extend every precaution to protect each member of our team as we carry out our diplomatic engagement during these unprecedented times.”

The trip came as leaders in the United States and Europe struggle to contain the coronavirus amid a new spike in cases. The White House itself experienced a fresh outbreak of coronavirus infections over the weekend, with at least five aides or advisers to Vice President Pence testing positive for the virus.

In Hungary, Berkowitz met with State Secretary Peter Sztaray and Deputy State Secretary Ferenc Dancs, said an official at the Hungarian Embassy in Washington. Berkowitz also participated in a roundtable discussion with officials about how the United States sees Central Europe. The two sides concluded that their “strategic goals are very much aligned regarding the region and our priorities,” the official said.

After the trip, Berkowitz’s positive test results prompted cables between the respective countries’ embassies in Washington and their capitals. Hungary is not reporting any new coronavirus infections related to the Berkowitz trip, the official said, and does not have any complaints about his conduct during the visit.

In response to questions about Berkowitz’s infection, which had not previously been reported, the State Department spokeswoman said, “We are closely monitoring daily Covid-19 developments, and continue to apply the best science and the current public health recommendations to support the entire team as we continue to achieve results on behalf of the American people.”

Across the country, the United States has suffered a 20 percent increase in newly diagnosed cases, a 13 percent rise in hospitalizations and an 11 percent rise in daily deaths over the past week, according to The Washington Post’s coronavirus tracker.

White House Chief of Staff Mark Meadows suggested Sunday that stopping the spread of the virus was no longer a possibility. “We’re not going to control the pandemic. . . . We are going to control the fact that we get vaccines, therapeutics and other mitigations,” he told CNN’s “State of the Union.”

Europe, meanwhile, reported more than 1.3 million new cases this past week, its single highest week count so far, according to the World Health Organization, as countries across the continent implement stricter social distancing rules and regulations.

As head of policy planning, Berkowitz oversees a staff of diplomats, academics, political appointees and civil servants who produce papers on long-term strategic planning and geopolitics. The purpose of the office varies depending on the secretary of state, at times filling the role of an in-house think tank and on other occasions handling special projects and tasks for the secretary of state.

Berkowitz came to the department from Stanford University’s Hoover Institution, where he taught constitutional law and political philosophy.

A State Department spokesman said the decision to delay the trip by Abrams “was made by the U.S. Embassy in London based on safety concerns amid rising infection rates.” The official declined to provide comment on why the embassy would approve a visit by Berkowitz, whose role does not involve pressing and immediate national security issues, and not Abrams, who works on two of the most consequential issues for the department, if not for objections from British officials following the Berkowitz trip.