Iran Human Rights, which is based in Norway and documents abuses of human rights in Iran, says 27-year-old Mehran Samak was executed in Bandar Anzali when celebrating the team's 1-0 loss to the United States.

The non-profit has also shared video purporting to show an unhappy crowd outside a medical office which has been refusing to release Samak's body.

Iran's participation at the FIFA World Cup was contentious because of widespread anti-Government protests which have gripped the country for more than two months.

The team did not sing the national anthem before their opening match versus England, which was widely viewed as a sign of support for the protests.

The anthem was also booed by Iranian fans in the stands.

Iran's players did sing the anthem before matches versus Wales and the US, but the boos remained.

The protests were sparked by the death of 22-year-old Mahsa Amini shortly after she was arrested by the so-called morality police for allegedly violating Iran's strict dress code for women.

Witnesses report that Amini was beaten and the police have widely been blamed for her death, sparking protests which have grown into the largest show of anti-Government sentiment seen in decades.

Iran shirts bearing Amini's name and flags with the rallying cry "Women, Life, Freedom" were taken into World Cup venues by some Iranians, but Qatari security officials confiscated them.

Iranians at the World Cup have complained of harassment at the hands of Qatari security officials and Iranian Govenermnt operatives working abroad.

Before the tournament there calls for Iran to be kicked out of the tournament, for reasons ranging from the persistent barring of women from football matches in Iran to the brutal crackdown against the protests, plus Iran's support for Russia's war in Ukraine, which has included supplying weapons.

Former FIFA President Sepp Blatter was among those who said Iran should be barred from the World Cup, as Russia had been from European qualifying.

Iran Human Rights says at least 448 people, including 60 children, have been killed by security forces responding to the nationwide protests.

There are fears for the safety of Iran players and their families when they return to the country, given their apparent show of support for the protests.

Before the tournament in Qatar, the Football Federation Islamic Republic of Iran vowed to punish beach soccer player Saeed Piramoon for celebrating a goal by imitating cutting his hair, an act carried out by hundreds of protestors.