DOHA - The World Cup kicks off in Qatar on Sunday in a high-stakes event for the nation which has faced a barrage of criticism and staked its reputation on delivering a smooth tournament, the first held in the Middle East and most expensive in history.

In a show of Arab solidarity, Saudi Arabia's crown prince and the presidents of Egypt and Algeria will be among political leaders at the opening ceremony led by Qatar's emir in a tent-shaped stadium at 5:40 p.m. (1440 GMT), before the first match between hosts Qatar and Ecuador. The U.N. Secretary-General will also be there.

Onstage, South Korean singer Jungkook of K-pop boy band BTS will perform a new official tournament song called Dreamers alongside Qatari singer Fahad Al-Kubaisi.

Alcohol has been banned at stadiums. Organisers say all are welcome while warning against pubic displays of affection.

FANS

Throngs of fans are already in Doha but the main rush is expected later this week, with daily flights shuttling in fans from neighbouring cities. On arrival, Argentina fan Julio Cesar said he expected a great atmosphere. "Even though there is no beer, we'll drink before the match."

As some visitors savoured their first sips at the launch of the FIFA Fan Festival on Saturday in central Doha, hundreds of workers, all men, gathered in a sports arena in an industrial zone on the city's edges where no alcohol was being served. They will be able to watch matches there, priced out of the stadiums many toiled to build along with other infrastructure for the event.

Wealthy gas producer Qatar is the smallest nation to host soccer's biggest global event, organised at a cost of $220 billion. Crowd control will be key with some 1.2 million visitors expected - more than a third of Qatar's population.

Workers were putting final touches on outdoor gardens and sidewalks on Saturday and carting construction material near the National Museum.

But at Lagoona Mall, where World Cup songs played on loop, life continued as normal with people queuing at the bank, sipping coffee in cafes and buying groceries.

"I came now because I don't know how bad the traffic will be later this week," said Esraa, an Egyptian woman stocking up at food retailer Carrefour.

(Reporting by Maya Gebeily and Andrew Mills; Writing by Ghaida Ghantous; Additional reporting by Yesim Dikmen, Thomas Suen, Gabrielle Tetrault-Farber, Ilze Filks and Karolos Grohmann in Doha and Omar Fhamy and Mahmoud Mourad in Cairo; Editing by William Mallard, Kirsten Donovan)