Geneva - FIFA threatened to suspend Switzerland from world football on Saturday if its national association does not discipline litigious club FC Sion within one month.
If the suspension takes effect, Swiss champion FC Basel would be prevented from playing Bayern Munich in the Champions League round of 16. The first leg is scheduled Feb. 22 in Basel.
Basel advanced from its Champions League group ahead of Manchester United, which would logically be reinstated by organizer UEFA.
Switzerland's Football Association has a further incentive to meet FIFA's demand - it is scheduled to host Lionel Messi and Argentina in a Feb. 29 friendly in Bern.
Swiss FA leaders were meeting Saturday to consider the FIFA ultimatum forcing Sion to forfeit most of its results this season by January 13.
Sion has breached football's rules in a legal saga since 2009 when FIFA imposed a one-year transfer ban for breaking transfer regulations in the signing of goalkeeper Essam El-Hadary.
On Saturday, FIFA criticised "the attitude of the club repeatedly trying to circumvent this decision in a legally abusive manner," in a statement issued after a meeting of its executive committee.
Sion's determination to fight football and legal authorities led it to launch a series of civil court actions against UEFA, which expelled it from the Europa League in September for fielding players that were signed during the transfer ban.
FIFA and UEFA were backed on Thursday by the Court of Arbitration for Sport, which upheld UEFA's right to kick Sion out of the competition based on FIFA's transfer sanction.
Sion refused to accept defeat, insisting it would challenge the decision at Switzerland's supreme court. Among its grounds for the appeal, Sion will claim that CAS is not truly independent.
FIFA stepped up the fight on Saturday by ordering the Swiss FA to enforce a ban on registering six Sion players signed in the offseason during the transfer embargo.
"As a consequence, all matches in which the relevant players participated shall be declared forfeit or three points shall be deducted respectively," FIFA said. "Should this deadline not be respected, the Swiss FA will be automatically suspended from January 14, 2012 onwards."
Under the terms of a FIFA suspension, a country's national and club teams, referees and officials are prohibited from taking part in international matches and meetings, or receive FIFA funding.
While FIFA and UEFA statutes clearly state their legal authority, and the role of CAS to judge appeals, the Sion case became problematic in August when the Swiss League gave into pressure from civil court interim rulings and provisionally registered the players.
That allowed Sion to escalate the dispute by selecting five of the players for a Europa League playoff against Celtic in August, which dragged UEFA into the legal fray.
The Swiss League then decided on December 8 that Sion could retain its match results and points gained using the six players: Pascal Feindouno, Mario Mutsch, Gabri, Jose Goncalves, Stefan Glarner and Billy Ketkeophomphone.
Some of Sion's opponents, who played those matches under protest, had been expected to challenge that league ruling at CAS.
However, FIFA's threats on Saturday require the Swiss FA to act.
Sion is currently third in the 10-team league, seven points behind leader Basel, and seemingly was on course to qualify for next season's Europa League before a points deduction that now appears inevitable. It has also reached the Swiss Cup quarterfinals.