Russian opposition leader Alexei Navalny on Thursday denounced the high cost of hosting the World Cup, alleging that much of the money was embezzled by businessmen seen to be close to President Vladimir Putin.
During a live video broadcast shortly after Russia's punishing 5-0 win over Saudi Arabia, Navalny -- known for anti-corruption investigations that target top officials -- said the result was "absolutely brilliant."
He then added: "It's great that Russia has this festival of football, but I don't understand why it absolutely had to cost you and me $14 billion."
The cost has been estimated at $13.2 billion, based on an average of the ruble-dollar rate over the years.
"I would like the World Cup to be held for a reasonable amount of money," Navalny said.
"I don't see it as a problem to simultaneously be glad of the Russian team's victory...and at the same time to be outraged at corruption," Navalny added.
He attacked oligarchs close to Putin who were involved in the construction of airports and stadia, naming billionaires Boris Rotenberg and his brother Arkady as well as Gennady Timchenko, who is seen as one of Putin's closest lieutenants.
"The Rotenbergs and Timchenko earned tens of billions of rubles. When I said earned, you have to understand stole," Navalny said.
"We understand very well... those people fantastically enriched themselves from the World Cup."
- 'So happy to be free' -
Navalny walked free on Thursday morning after serving a month-long sentence for organising an illegal protest.
"I'm with you again after a 30-day business trip. I'm so happy to be free," he wrote on Twitter.
The 42-year-old was sentenced a month ago after calling for the demonstrations ahead of President Vladimir Putin's inauguration for a fourth Kremlin term.
Navalny's lawyer and supporters called the trial politically motivated and Navalny said his rights had been violated.
Imprisoned several times for his political activities, Navalny wrote a tongue-in-cheek Instagram post about how jail conditions had improved ahead of the World Cup, including the installation of modern toilets and even goal posts for football games.
But he later clarified this had been intended as a joke and was not true. "Sorry guys, to everyone who believed me," he said.
"There are no toilets, there are still holes in the floor," he said. "There are no TVs and no goal posts and footballs in the exercise yards."
Navalny, who was barred from challenging Putin in March's presidential election, had called on Russians to stage rallies across the country on May 5 under the slogan "Not our Tsar".
Nearly 1,600 protesters were detained in 27 cities across Russia, according to OVD-Info, an independent monitor that tracks arrests.
Navalny was grabbed by police and carried away shortly after appearing in Moscow's packed Pushkin Square.
The European Union condemned "police brutality and mass arrests" following the demonstrations, which saw officers in several cities beat protesters with truncheons and drag them along the ground.
Navalny has faced a string of charges since he became the leading opposition figure campaigning against Putin's rule at mass demonstrations in 2011 and 2012.
He was jailed three times last year for breaking rules on organising demonstrations and had to travel to Spain for surgery after one of several street attacks left him nearly blind in one eye.
Russian opposition leader Alexei Navalny was grabbed by police and carried away during a protest against President Vladimir Putin in May