Four of the eight countries whose national leagues use FIFA-approved video review will not have match officials working at the World Cup.

FIFA confirmed on Thursday the 36 referees and 63 assistants who will work the 64 games in Russia. The same referees were provisionally selected in November.

FIFA has insisted World Cup officials will be fully trained to use the video assistant referee protocol, despite criticism of often slow and confusing decision-making since trials began in 2016.

Video review was this month voted into football's laws and approved by FIFA for the World Cup.

The World Cup officials represent 46 countries, though not Australia, Belgium, Portugal or South Korea, whose leagues have adopted VAR live trials.

Selection was based on "each referee's skills and personality, as well as his level of understanding of football and ability to read both the game and the various tactics employed by teams," FIFA said in a statement.

Still, FIFA said a "candidate's VAR experience in domestic leagues" will be a factor in choosing specialist video assistants from its pool of World Cup officials. That selection will be made after all attend a two-week seminar in Italy next month.

Four countries whose leagues use VAR — Germany, Italy, Poland and the United States — will have match officials in Russia.

Brazil, France and the Netherlands are among countries using VAR in domestic cup games that had officials selected by FIFA. No English officials were picked.

Only the United States has two referees selected: Mark Geiger, who also worked at the 2014 World Cup, and Jair Marrufo.

Sergey Karasev is the first Russian official selected for a World Cup since the 2006 tournament.

Ravshan Irmatov of Uzbekistan will work at his third World Cup, and should extend his all-time competition record of handling nine games.