Ten years after Brexit, most seasonal workers in Britain are from countries such as Kyrgyzstan and Tajikistan. Without them, agricultural chiefs say, many farms would fail.

The restrictions on half the continent have been called racist and unfair. “We don’t come to the United States because we’re running away,” one N.B.A. fan said.

Since the American-Israeli attack on Iran began, at least 12 civilians have been killed in oil-rich Gulf countries. All but one of them were foreign nationals.