The Rennes player, 29, was expected to leave with the rest of the squad for Los Angeles from Zurich earlier in the day.

"Unfortunately, Breel Embolo is currently unable to travel to the United States with the team," the ASF said.

"His ESTA (Electronic System for Travel Authorisation) authorisation had been approved until this morning.

"However, at 10:30 a.m., we were informed that his ESTA application had been placed under further review.

"We are currently in contact with the relevant authorities and expect that Breel will either join the team later today or travel tomorrow and join the squad then.

"We will keep you informed as soon as we have any further updates."

The federation did not explain why Embolo's visa had come under review.

In April, the former Schalke attacker was handed a 45-day suspended fine worth 3,000 Swiss Francs ($3,820) for threats he made during a night out in Basel in 2018.

Embolo scored in Sunday's 4-1 friendly win over Jordan, his 24th international goal on his 86th Switzerland appearance.

At the World Cup, Switzerland begin their Group B campaign against Qatar on June 13 before facing Bosnia Herzegovina and co-hosts Canada in the pool stage.

On Saturday, La Nati face Australia in their final pre-tournament friendly.

Subscribe to beIN SPORTS!