The four are Barbra Banda, Rachael Kundananji, Prisca Chilufya and Grace Chanda, will not be able to compete at the Yongchuan International Tournament, an invitational women’s event.

“Their failure to owes to additional travel measures introduced by the new administration in the United States”, Zambia Football Association general secretary Reuben Kamanga said in a statement, without specifying the “travel measures” referred to.

Recently, the Trump administration’s crackdown on illegal immigration, stepped-up checks of foreign student visa holders and a potential ban on travel from some countries, has made many foreigners who live in the U.S. question whether they should travel abroad in case they have difficulty re-entering the country.

Banda, the team captain, Chanda and Chilufya play for Orlando Pride, and Kundananji was under contract with San Jose-based Bay FC in the National Women’s Soccer League.

In an executive order signed in January, Trump told his Cabinet members to submit a report within 60 days that identifies countries with vetting so poor that it would “warrant a partial or full suspension” of travelers from those countries to the US.

US State Department spokeswoman Tammy Bruce said last month that the review was continuing and no list had been finalized. It is unclear whether China will be on the list.

Barbra Banda, the team captain, plays for Orlando Pride.