The incident occurred on Sunday at Moscow's Luzhniki Stadium during Spartak's match against Spartak Nalchik, from Russia's North Caucasus. The Luzhniki was host to the 2008 Champions League final between Chelsea and Manchester United.
The banner, consisting of seven Cyrillic letters, was held up by a group of fans in the stadium's Sector C. The identities of the other fans have yet to be established. Spartak Moscow won the match 2-0.
The public use of swearwords, or "mat" in Russian, is prohibited under the country's legal code and punishable by a fine or a custodial sentence of up to 15 days. However, the law is rarely enforced.
In another recent banner incident, Zenit St. Petersburg were forced to play their first home match of the 2009 season behind closed doors after the club's fans unfurled a banner insulting the memory of Lev Yashin, one of the country's greatest-ever players, during a game against Dynamo Moscow late last year.
The banner read "Your Yashin snuffed it, and Dynamo will snuff it."
Lev Yashin (1929-1990) is the only goalkeeper ever to have won the European Player of the Year Award. He spent his whole career, from 1949 to 1971, at Dynamo Moscow.
Russian football fans have a long tradition of bringing banners to matches. Before last year's Russia-England game in Moscow, "the largest banner in the world," depicting a bear, was unfurled before kick-off.
Banners are frequently of a less savory nature, however. In 2006, a swastika was displayed by Spartak Moscow fans at an away game in Yaroslavl, 250 km (155 miles) northeast of the capital.
