PICS: US-Iran fans turn up the heat in Qatar

Supporters of longtime foes United States and Iran on Tuesday flocked to a World Cup showdown in Qatar which some fans said was overshadowed by protests raging back in Iran and by years of enmity between the two countries.

The contest between the two nations, who severed ties more than 40 years ago, was being held with increased security to prevent a flare-up over the unrest that has gripped Iran since the death in custody of 22-year-old Mahsa Amini on Sept. 16.

US Secretary of State Antony Blinken, speaking in Romania, played down any link between the match and political tensions and said he hoped the game would "speak for itself", adding that he would be watching and cheering on his country.

Still, politics have spilled into the World Cup, the first to be held in a Middle East country.

Some fans gathering outside Al Thumama Stadium ahead of the match sought to highlight the protests which authorities in Iran have tried for more than two months to quell.

"Everybody should know about this. We don't have voice in Iran," said an Iranian living in the United States who gave his name only as Sam.

He raised his shirt to show a T-shirt underneath with the protesters's slogan: "Woman, Life, Freedom".

Another fan, who would not give his name, said he had mixed feelings about the game, saying the Iran players "don't represent (the) national team. They represent (the) national government's interests".

Steve Garcia, from Phoenix, Arizona, said the United States and Iran had their differences but could come together in sport.

"I know there's a lot of politics going on, but the way I look at it like - hey, we're here to have a common bond, which is the sport of football, soccer," he said.