The United States Olympic and Paralympic Committee (USOPC) says it needs clarification of “the conditions for neutrality” for Russians and Belarusians to compete at Paris 2024.
President Gene Sykes said the USOPC “stands in solidarity with the people and athletes of Ukraine”.
However it would consider a process allowing “truly neutral” Russian and Belarusian athletes to compete.
Ukraine has threatened a boycott if a ban on those athletes is not upheld.
The International Olympic Committee (IOC) has said it will “explore a pathway” for athletes from those nations to participate.
It insisted the Games “can inspire us to solve problems by building bridges”, but no decision has been made on what practical steps it will take.
The United Kingdom is among 36 countries to have pledged support for an ongoing ban, put in place following Russia’s invasion of Ukraine in February 2022.
The USOPC said it was concerned about how the IOC would determine the criteria for a neutral athlete.
“Although the conversation has shifted over time, our position has not,” said Sykes.
“We encourage the IOC to continue exploring the process that would preserve the existing sanctions, ensuring only truly neutral athletes who are clean are welcome to compete.
“Only if these conditions of neutrality and fair, clean competition can be met do we believe that the spirit of the Olympic Games can prevail.
“What will neutrality really mean, what will the conditions for neutrality be?”
Ukraine president Volodymyr Zelensky has said Russian participation at the Olympics “cannot be covered up with pretend neutrality or a white flag” and the nation has “no place at sports and Olympic competitions” while the invasion continues.
The IOC has urged Ukraine to drop threats of a boycott as it seeks to “promote peace through sport”, having made Russian and Belarusian athletes compete under a neutral flag at the Winter Paralympics in March 2022.
The UK government hosted a summit in February which included representatives from the US, and asked Olympic sponsors to support a ban at the 2024 Paris Games and press the IOC on the issue.
In response, the IOC said the UK government should “respect the autonomy of sport”, adding: “It is not up to governments to decide which athletes can participate in which international competitions.”
Germany’s fencing federation cancelled a women’s foil World Cup event on Friday after the sport’s governing body reversed a ban on athletes from Russia and its ally Belarus.