Fraudsters have tricked scores of Nigerians by selling them football
Some Nigerians told AFP they used the official Fan IDs to come to Russia with the promise of finding work or even playing professional football themselves.
Others said they came to watch World Cup matches but got stranded when their return plane tickets were cancelled by bogus travel agencies that booked them.
Ismail Olamilekan, 21, and his brother Sodiq, 25, said they paid 250,000 naira (600 euros, $700) each to a man in Lagos for their Fan IDs.
"The man told us that with the Fan ID we could get a job and stay here," Ismail told AFP at a hostel on the outskirts of Moscow.
"But when we got here we discovered that it was a fraud, that he had just collected the money and lied to us."
The plastic-coated passes issued by the Russian government enable foreign fans with match tickets to enter the country without a visa during the World Cup -- but they expire before the end of July.
It was not clear how the bogus agents obtained the Fan IDs that they sold.
A FIFA spokesman stressed that the Fan IDs system was implemented by the Russian communications ministry.
FIFA "continues to make efforts to identify and curb unauthorised ticket sales", he added.
Foreign ministry spokeswoman Maria Zakharova told a news briefing it was a matter for the consular authorities of the countries concerned.
"You can't rule out that some of the foreign guests, taking advantage of visiting the World Cup, are counting in some way or another, usually illegally, on crossing the Russian border and entering one of the European countries," she added.
The Olamilekan brothers spent about a thousand dollars each for their plane fare to Moscow, on top of what they paid separately to the agent.
"In Nigeria I play football. He told me that if I started working I can also start a (football) career in Russia," Ismail Olamilekan said.
A fellow Muslim was allowing the brothers to sleep in his hostel until their return flight on July 22.
Other Nigerians however found themselves stranded in Russia after fraudulent "agents" who booked return flights for them then cancelled the bookings to get a refund.
One group of about a dozen Nigerians spent days sleeping at Moscow's Vnukovo airport.
Some of them told AFP they paid more than a million naira each to an agent for a package including flights, match tickets and a fan ID.
"We've been sleeping on the floor like fools. We've got no place to go," said Alonge Ademola, 35, a cement dealer from Lagos.
"We really do want to go back to our country. We've cried, we've wept, but still no solution."
Russian charity Alternativa said it had helped about 50 Nigerians stranded in Russia and estimated there were about 200 in difficulty overall.
"With globalisation the opportunities for criminals are also increasing. The Fan IDs make an extremely profitable business for them," said the group's spokeswoman, Yulia Siluyanova.
Around 50 Nigerians spent the night of Thursday to Friday on the pavement in front of the Nigerian embassy in Moscow.
Nigerian embassy spokesman Olumide Ajayi told AFP on Friday that it had made arrangements to house 57 stranded Nigerians and would work with Russian authorities and airlines to find a way to send them home.
The Olamilekan brothers meanwhile are waiting to board the return flights. They funded the whole trip with money their parents borrowed.
"We don't have any option but to go back home and work and pay our parents' debts," Ismail said.
"I spoke to them last night. They asked if we've got a job and if we're living well and I decided to tell them yes. I don't like lying to my parents," he said.
"I still give thanks to God because he has taught me a lesson."