Manchester City manager Roberto Mancini is disappointed with the standard of refereeing in the Premier League.
There have been several controversial decisions in recent weeks, most notably City's title rivals Manchester United winning two debatable penalties.
"When I was in Italy I always thought, here, there were the best referees," said Mancini. "My idea has changed.
"I am not frustrated. In Italy we say every place is the same. The rules are not the same for everyone."
Asked if he was referring to United, Mancini said: "I'm not saying this; I don't want to say this.
"I said the rules, maybe sometimes, are different. I can say it is a very strange situation."
United, who hold a five-point lead over City at the top of the table, were awarded a controversial penalty in Sunday's win over Aston Villa, with boss Sir Alex Ferguson admitting Ashley Young "overdid" his fall.
"After some of the some of the situations I have seen in the last three or four weeks, I think it is really difficult for us," said Mancini ahead of City's trip to Wolves on Sunday.
"For us it is important to finish well this season. We want to try to win the next game. That will be difficult. Wolves are bottom of the table and it will be a tough game."