"On Friday we received documents from UEFA requiring the club to limit ticket sales for Thursday's game to 50 percent of stadium capacity," Lech's spokeswoman Joanna Dzios told AFP.

The European football governing body also fined Lech 20,000 euros (27,000 dollars) and ordered them to play one match behind closed doors -- although the latter penalty was suspended for two years.
Lech said they would appeal against the ruling.

Lech were accused of failing to respect security rules during their previous Europa League home game against Juventus in December, which clinched them a berth in the last 32 of the competition.

UEFA took issue with problems at the ground's exits, which were clogged by fans, as well as overly-narrow access areas to some stands and mistakes in seat numbering.

The upgraded, 43,000-capacity Stadion Miejski in the western city of Poznan -- also one of Poland's four venues for the 2012 European Championship -- was opened in September and has proven a hit with the public.

It is owned by Poznan city hall, which in turn grants Lech rights to the arena.