Responding to a question about President Donald Trump's order banning citizens from six Muslim-majority nations from traveling to the United States, FIFA boss Gianni Infantino said any nation bidding for the tournament would have clear rules.
"We are now in the process of defining the bid requirements," he said.
"In the world there are certainly many countries with travel bans, visa requirements and so on and so forth.
"What is obvious is that when it comes to the World Cup, like the Olympic Games ... any team, including the supporters and officials of that team who have qualified, need to have access to the country. Otherwise there is no World Cup."
FIFA has ruled out a bid from Europe or Asia, leaving the CONCACAF region as frontrunner for a tournament set to expand to 48 nations from 32.
The United States last hosted the World Cup in 1994 and Mexico in 1986.
Los Angeles is also bidding against Paris for the 2024 Summer Olympics with a vote on that due in September.
Victor Montagliani, the CONCACAF president, said last month that a wall planned by Trump along the US-Mexico border would not present an obstacle to co-hosting the event.
Regional soccer officials have, however, been tight-lipped about the executive order.
The head of European soccer body UEFA warned last month that restrictions could damage any US bid.
"It will be part of the evaluation, and I am sure it will not help the United States to get the World Cup," UEFA president Aleksander Ceferin told the New York Times.
"If players cannot come because of political decisions, or populist decisions, then the World Cup cannot be played there."
"The requirements will be clear. Then each country can make up their decision whether they want to bid or not," said Infantino. "It's nothing to do with the US or not the US, it's a general sporting criteria."