MEXICO CITY : FIFA President Gianni Infantino brushed off criticism over World Cup visa issues and sky-high ticket prices on Wednesday in a defiant eve-of-tournament press conference.

Speaking in Mexico City ahead of the World Cup's opening game at the Estadio Azteca on Thursday, Infantino launched a spirited defense of the organisation of the 48-team extravaganza being co-hosted by the United States, Mexico and Canada.

Infantino and FIFA have come in for stinging criticism over the eye-watering costs of World Cup tickets while Donald Trump's immigration crackdown has seen a top referee, Iranian team officials and fans refused entry to the United States.

Infantino insisted that tickets to the tournament -- which in some cases have topped $30,000 -- had been priced appropriately, citing a small number of $60 tickets that were made available in response to criticism.

"Let me just say that our entry price, which is 60 dollars, is the lowest entry price of any of the American sports in the play-off phases," Infantino said.

"Our average price which is below 500 dollars is again the lowest of the American sports on average."

- 'Unfortunate' Somali -

Infantino also played down the controversy surrounding Somali World Cup referee Omar Artan, who was refused entry to the United States after arriving in Miami last Saturday following security concerns raised by US immigration authorities.

FIFA has since confirmed Artan, who the US State Department later said had "associated with suspected members of terrorist organizations," will play no part in the tournament.

"It is unfortunate what happened to the referee from Somalia," Infantino said.

"We don't control everything... Sometimes it's good to chill, relax, we work on everything, we try to solve everything.

"Sometimes to immediately start screaming and shouting has the opposite effect of finding a solution."

The FIFA leader also portrayed Iran's participation at the World Cup in the midst of its military conflict with the US as a victory for his organization.

"People were saying Iran couldn't come to the World Cup," Trump said. "There are challenges, it's not easy, but I don't know who else would have been able to ensure in these circumstances -- which we could not influence -- Iran could come and play."

Infantino's close relationship with US President Trump has also come under scrutiny in the build-up to the tournament.

But Infantino maintained Trump had played a critical role in World Cup preparations.

"Without his engagement and involvement, I think it would have been, simple as that, impossible to organise a World Cup in the United States," Infantino said of Trump.

In Washington on Wednesday, Trump confirmed he plans to attend some World Cup matches, without providing details.

"I spoke to Gianni this morning... he said there's never been anything close" to the success of the coming tournament, the US leader said.

Meanwhile, concerns were rising that Thursday's opener between hosts Mexico and South Africa in Mexico City could be disrupted by social unrest.

Protesters Tuesday blocked an avenue leading to the Estadio Azteca although lines of police prevented the demonstrators from reaching the stadium.

Thousands took part in the demonstration following a week of action that Mexican President Claudia Sheinbaum has called a "provocation."

Sheinbaum insisted Wednesday that "everything is under control" for the curtainraiser.

- Weather disruption -

The spectre of Mother Nature disrupting the tournament also reared up on Wednesday, with England's final World Cup warm-up game against Costa Rica delayed after a thunderstorm hit Orlando, Florida.

Torrential rain and lightning flashes forced the kick-off to be delayed, echoing the problems that marred last year's Club World Cup, where several games were disrupted by weather.

When the action started, England eased to a 3-0 win with new Barcelona signing Anthony Gordon starring with a goal and an assist, making his case for a starting spot for his side's World Cup opener against Croatia on June 17.

Portugal wrapped up their preparations by beating Nigeria 2-1, with goals from Pedro Neto and Francisco Conceicao making up for an off night for Cristiano Ronaldo.