US Secretary of State Marco Rubio has said his country's World Cup team had been "screwed" and called for an appeal after star striker Folarin Balogun was sent off against Bosnia.

Washington's top diplomat tackled the sporting controversy on Thursday a day after Balogun was given a red card in the 2-0 US win. Balogun is now set to miss his side's last-16 showdown with Belgium.

"It was great. They got screwed with that red card," Rubio told reporters during a brief appearance in the White House briefing room when asked how the co-hosts were doing in the tournament.

"There needs to be an appeal process for that. It's probably too late for that, right?" added Rubio, who was leading a group of people on a tour.

While he weighed in on the World Cup, US President Donald Trump's diplomatic pointman declined to answer questions on Lebanon and Iran.

"Guys I'm not here to talk about the news," Rubio added.

Coach backs Balogun

According to FIFA regulations, Balogun is automatically suspended for his team's next match, and the suspension cannot be appealed, a spokesman for the governing body told journalists on Wednesday.

In the 64th minute of Wednesday's knockout game against Bosnia and Herzegovina, Balogun was controversially judged after a VAR review to have stamped on the back of defender Tarik Muharemovic's foot.

USA's Argentine coach Mauricio Pochettino said after the match that Balogun — who scored the US opener in Wednesday's game — should "never" have received a red card.

Pochettino said it "should be fair" to appeal the decision, but said he would have to consider "different options" if it is not.

Balogun — who was born in New York but raised in England and now plays for French club Monaco — has scored three times for the USA this World Cup and his loss will be a major blow.