FIFA has threatened to suspend Switzerland from world football if its national association does not discipline litigious club FC Sion by Jan. 13.

If the suspension took effect, Swiss champion FC Basel would be prevented from playing Bayern Munich in the Champions League round of 16 in February.

Basel advanced ahead of Manchester United, which would logically be reinstated.

Sion has breached football's rules by launching a series of civil court actions against UEFA since being expelled from the Europa League last month for fielding ineligible players.

FIFA says Sion has acted in a ''legally abusive manner.''

FIFA on Saturday ordered Switzerland's Football Association to enforce a ban on registering six Sion players signed during a transfer embargo.