FIFA has issued Iran with a fine and a warning over "several religious manifestations" during a recent World Cup qualifier in Tehran.
The 1-0 victory over South Korea at the Azadi Stadium was held on the first of two mourning days on the Shia Muslim calendar.
According to BBC Sport, Iranian fans were asked to sing religious chants and wear black, which was seen to go against FIFA's ban on political, religious or commercial messages at matches.
Also fined on Thursday by the world football governing body were Albania, Croatia, Kosovo, Brazil, Paraguay, Estonia, Ukraine, Chile and Argentina, for "discriminatory and unsporting conduct by fans".
