Hydration breaks at the World Cup are "purely a sporting matter" and bring "no additional revenue for Fifa", president Gianni Infantino has said.

Three-minute pauses midway through both halves of all World Cup fixtures were introduced in an attempt to help players deal with extreme heat during the tournament in North America.

But there has been a mixed reaction to the breaks from players and coaches, while there have been boos from some sections of supporters at stadiums when they have been signalled for by the referee.

Television broadcasters in several countries have shown adverts while the hydration breaks have been in progress - although that is not the case in the UK.

Some matches, such as England's draw with Ghana on Tuesday, have been played in more comfortable temperatures and others staged inside air-conditioned stadiums with a roof.

Infantino explained that one of the main reasons for having breaks in every match is to create "equal conditions" for all competing nations.

He said: "There is no additional revenue for Fifa, as all commercial agreements were signed well in advance.

"This is not a financial issue for us. For us, it is purely a sporting matter."

Managers and coaching staff are allowed to discuss tactics with their players while the breaks are taking place.

Infantino said: "The main reason [for the breaks] is the heat, but we also have to understand that in a competition like the World Cup, played over 39 days, with teams potentially playing eight matches in those 39 days, having a moment to rest is extremely important.

"What matters even more to us is ensuring that all teams, in every match, are playing under the same conditions.

"And it's very difficult to accept that a coach might have the opportunity to influence a match by making adjustments simply because it is hotter, while in another match, where the temperature is slightly lower, the same coach does not have the same opportunity.

"We want to ensure equal conditions for everyone and that's why these breaks are implemented in every match."

Experts have told BBC Sport an average 30-second World Cup advertising slot on Fox Sports costs between $200,000 (£152,000) and $300,000 (£227,000), rising to $750,000 (£567,000) during USA matches and the final stages.

That means advertising during hydration breaks is likely to generate more than $250m (£189m) in the USA alone.