Iran will pose a significant test to Fifa’s “football unites the world” slogan on Monday by becoming the first nation in World Cup history to compete on the soil of a host country with which it is at war.

The national team’s opening match against New Zealand in Los Angeles will begin amid ongoing hostilities between Iran and the US that have grown sharper in recent days, as a shaky ceasefire has not held and efforts toward a negotiated settlement have stalled.

The tense setting undercuts the unity message promoted by Fifa president Gianni Infantino, according to analysts.

“Despite Fifa’s hopes that this could be an apolitical World Cup, it is the most politically charged World Cup ever, and the Iran-United States-Israel conflict sits right at the center of it,” said Jules Boykoff, a politics professor at Pacific University in Oregon and a former professional footballer.

“There has never been a World Cup where one of the hosts openly threatens war crimes against one of the participating nations, and that participating nation, in turn, is striking other participating nations. The degree of novelty is unprecedented.”

Iran’s players will take the field at So-Fi stadium after months of uncertainty over whether they would be permitted to participate at all, following Donald Trump’s suggestion that it would be safer for them to stay away.

Questions about their involvement were resolved only this week after squad members received US visas, although several officials have been barred from entry, including the president of Iran’s football governing body, Mehdi Taj, because he once belonged to the Islamic Revolutionary Guard Corps.

The uncertainty has disrupted preparations and created logistical challenges that could hinder the team’s progress in the tournament.

Amid concerns about their reception in the US, the squad’s training base was moved from Arizona to Tijuana in northern Mexico, where the players arrived this week after three weeks at a camp in Turkey. The team will travel to Los Angeles on match day and return to Mexico right afterward to avoid staying in the US overnight.

The same pattern will apply for later matches against Belgium in Los Angeles on 21 June and against Egypt in Seattle five days later. The Egypt game has already sparked controversy after local authorities designated it the city’s Pride match to align with that weekend’s LGBTQ Pride festival, drawing protests from Iran and Egypt, where homosexuality is illegal.

The situation has been further complicated by an ideological struggle between Iran’s Islamic regime and its critics over who the team represents and where its loyalties lie.

In normal times the players could expect strong support in Los Angeles, home to a large ethnic Iranian community that has given the city the nickname “Tehrangeles.”

Yet strong opposition to Iran’s theocratic rulers among many expatriates could weaken that backing.

A key move in what appeared to be a contest for the team’s identity came this week with an officially approved World Cup video posted on social media that portrayed the players as representatives of the regime’s Shia Islamist ideology.

It features footage of the players set to a religious eulogy honoring the imams Ali and Hussein, the two most revered figures in Shia Islam after the prophet Muhammad, and references the seventh-century Battle of Karbala.

Alex Vatanka, head of the Iran programme at the Middle East Institute in Washington, criticized the video. “The World Cup was a chance for Tehran to address Iranians as a nation. Instead, it chose to address them as an Islamist ideology,” he wrote, labeling the video “a major own goal.”

Reza Pahlavi, son of Iran’s last shah Mohammad Reza Pahlavi, condemned attempts to depict the team as emissaries of regime ideology.

He has positioned himself as an alternative to the ruling theocracy and shared a video underscoring its persecution of footballers. “Today, many Iranians no longer see the national team as a team that represents the nation,” the video’s female narrator states.

After lobbying from the Iranian football federation, Fifa has prohibited displays of national flags from before the 1979 Islamic revolution that show a lion and sun, symbols of the monarchy still used by many regime critics.

Pahlavi condemned the ban, and some regime opponents pledged to circumvent it by smuggling in the old flag beneath the official one.

Iranian officials have stated the team will halt play if banned flags appear or anti-regime chants occur during a match.

Mahmood Ebrahimzadeh, a former Iran international now living in Maryland, predicted that many US-based Iranians would withhold support. “I would say the majority do not want to support the national team,” said Ebrahimzadeh, who leads an organization of retired Iranian athletes living in exile. “As a soccer player, it is unfair.

“Everybody expects those players to speak out for the people against the government. But they are not strong enough in education to speak about human rights. And the country is in a very difficult situation with the war against America and Israel, so it is hard right now to use football to speak out.”