NYON, Switzerland (AP) -- UEFA has punished three Champions League clubs, including former winner Steaua Bucharest, for racist behavior by fans at matches last month.
Steaua, the 1986 European Cup champion, Debrecen and Maribor must close stadium sections at the next Champions League or Europa League match they host, UEFA said in a statement on Tuesday.
The Romanian champion's sanction takes effect Wednesday. Two sections of the National Arena will shut against Kazakhstan champion Aktobe in a third qualifying round, second-leg match.
UEFA operates an escalating scale of sanctions with further racism incidents provoking full stadium closures, leading to possible disqualification from competitions.
''All forms of racist behavior are considered serious offences against the disciplinary regulations and are punished with the most severe sanctions,'' UEFA said.
UEFA's disciplinary panel acted on reports of racist incidents when Steaua beat Norway's Stromsgodset 2-0 in a second qualifying round match on July 23.
Debrecen of Hungary must shut sector B of its ground after fans showed an ''illicit banner'' during a 2-0 win against Northern Ireland's Cliftonville on July 22.
Slovenia's Maribor must close sector 'Jug' of its stadium after racist behavior when beating Zrinjski of Bosnia-Herzegovina 2-0 on July 22.
Debrecen and Maribor play away in second-leg matches Tuesday.
In a fourth case from the Europa league, UEFA ordered Chikhura Sachkhere of Georgia to close the section of its stadium used by 'ultras' fans on Thursday when Neftchi Baku of Azerbaijan visits. It followed incidents during a goalless draw with Bursaspor of Turkey on July 24.
UEFA is in the second season of a stricter regime of sanctions for racism incidents involving players, officials and fans.
Evidence is typically provided by monitors from the Fare network of fan groups, formerly known as Football Against Racism in Europe.