Coach Gregg Berhalter apologized for US Soccer tweeting an altered Iran flag, but insisted he and the USMNT knew nothing of it in a tense World Cup pre-match news conference.

The Group B meeting between the US and Iran was always likely to be politically charged, even before previous results made it a qualification decider.

In an early answer at his media briefing on Monday, Berhalter sought to head off such questions, saying: "When I think about this match, I know a lot of other constituents have a lot of feelings towards it."

"For us, it's a soccer game against a good team. It's not much more than that. It's a knockout game, both teams are desperate to go to the next round. That's how we're looking at this match."

Soccer Alex Morgan to play for Team USA in Women's Gold Cup after Mia Fishel injury

But that did little to quell the line of questioning, which was not helped by a Twitter post on Sunday.

US Soccer uploaded an edited Iran flag without the emblem of the Islamic Republic in a move to support protestors in the country, where there has been unrest since the September death of Mahsa Amini, a 22-year-old woman who died in police custody after being arrested for her refusal to wear the mandatory hijab.

That post prompted outrage in Iran, including state-affiliated media Tasnim calling for the United States to be removed from the World Cup.

Team captain Tyler Adams, who was corrected on his pronunciation of "Iran", said the USMNT "support Iran's people and Iran's team" but are "laser-focused on this match".

Berhalter later expanded more on the topic: "We had no idea about what US Soccer put out, the staff, the players had no idea. Our focus is on this match."

"I don't want to sound aloof or not caring in saying that, but the guys have worked really hard for the past four years."

"We have 72 hours between England and Iran, and we really are just focused on how to get past Iran and go to the knockout stage of this tournament."

Soccer MLS chief blasts referees union after members reject tentative contract agreement

"Of course our thoughts are with the Iranian people, the whole country, the whole team, everyone, but our focus is on this match."

When Berhalter was asked again about the Twitter post, he said: "I can only reiterate that the players and the staff knew nothing about what was being posted. Sometimes things are out of our control."

"We believe it'll be a match where the result depends on who puts more effort on, who executes better on the field, not what happens outside."

"We can only apologize on behalf of the players and the staff. It's not something we're a part of."

Former USMNT coach Jürgen Klinsmann had made matters worse by accusing Iran of having "worked the referee" against Wales, suggesting getting to the match officials and pushing the boundaries of acceptability was "part of their culture".

Iran boss Carlos Queiroz responded in a blistering thread on Twitter, calling for Klinsmann to be sacked from a role with FIFA, but he would not answer questions on the matter at his own news conference.