Iran footballers lining up for an international friendly match this week covered their national team badges and wore black in an apparent act of solidarity with protesters in the country.

The players donned plain black jackets as they lined up for the national anthem on Tuesday against Senegal, which concealed the kits' national flag and colors.

Despite being played in Austria, the match was held behind closed doors due to an order by Iran's football association which held the rights to the game, The Guardian reported, seemingly in order to avoid protests in the stadium.

Iranian star Sardar Azmoun voiced support for the young Iranians who have taken to the streets to protest police brutality after the death in custody of  22-year-old Mahsa Amini.

He hinted in an Instagram post that players had been gagged by authorities about commenting on the protests.

He wrote: "The ultimate [punishment] is to be kicked out of the national team, which is a small price to pay for even a single strand of Iranian women’s hair. Shame on you for easily killing the people and viva women of Iran. Long live Iranian women!"

There has been no word from the players that the jacket-wearing line-up was a reference to the political development but Iranians have interpreted it as support for the protests.

A small group of Iranians gathered outside the BSFZ-Arena in Vienna to support protesters in Iran angered by Amini's death after she was allegedly beaten into a coma by police

She was detained for allegedly not covering her hair sufficiently. Iran has strict dress codes targeting women, including the covering of hair.

Security forces have brutally suppressed the protests triggered by Amini's death killing at least 76 people, according to activists.

Iranian football legend Ali Karimi has voiced support for the protests triggered by Mahsa Amini's death.

Karimi paid tribute to Amini on Twitter under the hashtags 'I am Iran' and 'Women, Life, Freedom'.

He also mourned prominent 20-year-old protester Hadis Najafi, who was reportedly shot and killed in the city of Karaj on Sunday, according to Newsweek.