Sportswear giant Nike says it has withdrawn its supply of boots to Iranian footballers ahead of the World Cup because of new US sanctions.
The decision has frustrated Iranian players and head coach Carlos Queiroz, who asked Fifa to "help" his players.
He vowed to reimpose economic sanctions that were waived when the deal was signed in 2015.
"US sanctions mean that, as a US company, Nike cannot supply shoes to players in the Iranian national team at this time," the company said in a statement published by ESPN.
"Sanctions applicable to Nike have been in place for many years and are enforceable by law."
Queiroz, who has formerly coached Portugal and Real Madrid, told reporters: "Players get used to their sports equipment, and it's not right to change them a week before such important matches.
"We are only managers and footballers, and should not get involved in such matters. But we are asking Fifa to help us with this."
A number of Iranians have started a campaign on social media to boycott Nike products in response, using the hashtag "No to Nike".
"When Iran refuses to play against Israel it is political interference in sports, but when Nike refuses to supply boots to Iranian players due to sanctions, Fifa doesn't say a word," said one user on Twitter.
In a widely-shared video, an Iranian man who described himself as a dentist threw a pair of Nike shoes in a bin, saying the company's decision was "an insult to my people and all football lovers".
Another user said Iranian players should have pre-empted Nike by announcing they would no longer wear Nike boots. "There was a time our sportsmen were symbols of national pride. They have now become symbols of humiliation," he said.
However, some Iranians say as a private US company, Nike had no other choice.
"Nike is a private company and its only objective is to satisfy its shareholders. It is normal that it is withdrawing its supply of boots to Iran for fear of economic penalties," tweeted one user.
"Nike is not a member of Fifa and does not have to follow its regulations. This is the impact of politics on trade rather than political interference in sport," said another.
This is not the only inconvenience hampering Iran's World Cup preparations.
Iran's football federation suspended relations with its Greek counterpart last month after a friendly between the two was cancelled amid tensions between Greece and Turkey.
A second warm-up against Kosovo was also cancelled.
Reporting by BBC Monitoring Iran Team