South American football's governing body on Saturday postponed two rounds of 2022 World Cup qualifiers scheduled later this month because of Covid-19 quarantine rules affecting European-based players and the threat of clubs refusing to release their international stars.
The decision to call off the double matchday, which was set to take place on March 25-26 and 30, was "due to the inability to have all the South American players in a timely manner," CONMEBOL said in a tweet.
The confederation said it would study the options available in order to reprogramme the matches postponed.
FIFA has given clubs dispensation to prevent players who may be affected by coronavirus regulations from joining up with their countries during the upcoming international window.
Manchester City boss Pep Guardiola on Friday joined Liverpool counterpart Jurgen Klopp in vowing to stop his players from flying overseas for internationals if they would be required to quarantine on their return.
Under current coronavirus guidelines, players arriving in Britain from "red-list" countries, including Brazil and Argentina, are subject to 10 days' hotel confinement.
Guardiola said he never wanted to stop players from representing their country, but would make an exception as his side closed in on the Premier League title.
"I think it makes no sense if the players go to the national team and then have to isolate for 10 days when they come back," he said.
"They are not going to fly. That's for sure. If they can fly, play with the national team and come straight back to training, they'll fly."
- Brazil-Argentina showdown rearranged -
Brazil had been due to play Argentina in Recife on March 30, in a meeting of the top two countries in South American qualifying for next year's World Cup in Qatar.
The five-time world champions were also set to play Colombia in Barranquilla four days earlier.
Even if Brazil's players received the all clear, Colombia's Health Minister Fernando Ruiz pointed out that air travel between Colombia and Brazil is still suspended due to the latest wave of coronavirus infections.
"Right now, I think it's difficult to authorise any flight leaving from Brazil and I don't have any justification to authorise such a flight," Ruiz told Blu Radio.
Paris Saint-Germain risked losing Neymar, Marquinhos and Angel Di Maria for a game against Ligue 1 leaders Lille had they joined up with their respective national teams.
French government regulations stipulate that anyone entering the country from outside Europe must self-isolate for seven days on arrival and present a negative Covid-19 test at the end of that period.
PSG coach Mauricio Pochettino conceded it was "a complicated matter" but called for a "fair and just agreement for everyone".
"We have to find the best solution so the competitions remain as fair as possible, and so the players receive equal treatment regardless of the country where they play," the Argentine said.
Some European nations have moved fixtures in order to try to avoid travel restrictions.
Portugal have announced they will play their "home" World Cup qualifier against Azerbaijan in Turin, while Norway will face Turkey in Malaga.