UEFA president Aleksander Ceferin has ruled out using Video Assistant Referees (VAR) in the Champions League and Europa League from next season.
VAR has been trialled in several competitions around the world throughout this season, but Ceferin told the 2018 UEFA Congress that there was not yet sufficient confidence in the system to implement it into UEFA competition.
FIFA is almost certain to use VAR at this summer's World Cup finals in Russia, and on Saturday the International Football Association Board (IFAB) is expected to vote on changing the laws of the game to officially introduce VAR.
The German Bundesliga, which has been testing VAR, and 2. Bundesliga have both indicated they want to use VAR from next season, but ongoing questions over how well it is understood by both officials and fans have led UEFA to take a step back.
"I don't think they [IFAB] will make it a law but they will allow everybody to test it," Ceferin said ahead of Saturday's vote.
"I think that it will be probably used at the World Cup. We will not use it from the next season in the Champions League. I can tell you that. But I'm absolutely not against it. I think there's no way back any more. But we have to educate the referees properly.
"Nobody exactly knows how it works, which might be a big problem. So, let's see what happens at the World Cup and then we will decide.
"We shouldn't rush into decisions that are not clear. For me, I see a lot of confusion from time to time. But that doesn't mean that I'm against it or that I don't think it will happen."
Meanwhile, UEFA has announced that Phil Townsend has been appointed managing director of communications. He had been performing the same role at Manchester United for the last 14 years and will join UEFA in June.
Townsend said: "I have always had the highest regard for UEFA and its work in the development of the game across Europe. It is a great honour to have been asked to take on this role. It was a difficult decision to leave United after so many years working alongside so many good people in a club with such huge global significance in the game but this is a wonderful opportunity at a very important time for European football."