CEO Tim Hinchey sent a letter Friday to his counterpart at the USOPC, Sarah Hirshland, calling for the delay.

"Everyone has experienced unimaginable disruptions, mere months before the Olympic Games, which calls into question the authenticity of a level playing field for all," Hinchey wrote. "Our athletes are under tremendous pressure, stress and anxiety, and their mental health and wellness should be among the highest priorities."

Only hours before receiving the letter, the USOPC leaders essentially repeated the IOC line — that while athlete safety would always be their top priority, it was too soon to employ drastic measures, and that they would press forward with logistical preparations for a July 24 start.

"The decision about the games doesn't lie directly with us," USOPC board chair Susanne Lyons said.

She and Hirshland showed no appetite for getting out front on the postponement issue, which is gaining more steam among athletes, some Olympic leaders and, now, one of America's most high-profile national governing bodies.

Left unsaid was the impact the USOPC's voice could have in moving toward a postponement. In theory, no national Olympic federation has more power to alter the shape of an Olympics than the one in the U.S., which brings 550 athletes and its billion-dollar broadcaster, NBC, to the show every two years.

"We urge the USOPC, as a leader within the Olympic Movement, to use its voice and speak up for the athletes," Hinchey wrote.

Other sports organizations were adding their voices.

Nic Coward, the chairman of UK Athletics in Britain, told BBC Sport that leaving the Olympic starting date unchanged "is creating so much pressure in the system. It now has to be addressed."

And the CEO of Swimming Canada, Ahmed El-Awadi, put out a statement saying: "We hold the opinions of our brothers and sisters at USA Swimming in high regard, and share many of the same concerns around health and safety."

After the USA Swimming news, Hirshland and Lyons sent out a joint statement, emphasizing the multiple moving parts that are influencing any decision from the IOC, and looking ahead to an important IOC meeting next week, at which leaders will receive feedback from countries.

"Rest assured we are making your concerns clearly known to them," the statement said.

USA Swimming isn't alone. A growing number of athletes are calling for more decisive action from Olympic leaders: "The most infuriating part of this whole thing is it feels like the IOC is going to do what they want, regardless of what the athletes think," U.S. Olympic silver-medal pole vaulter Sandi Morris  tweeted late Thursday.

A member of the Japanese Olympic Committee, 1988 judo bronze medalist Kaori Yamaguchi, has also been vocal in calling for a postponement.

But there is also a contingent of athletes who are not speaking up as loudly on social media.

"They want the Olympic and Paralympic community to be very intentional about the path forward — and to ensure that we aren't prematurely taking away any athletes' opportunity to compete in the Olympic and Paralympic Games until we have better clarity," the USOPC leaders said in their statement.

Han Xiao, the chair of the athletes' advisory council, said the varying views are why his group has not made any definitive statements encouraging a postponement.

"We are specifically asking for more transparency around the decision-making process, more information about what measures and conditions are being discussed, and less public emphasis on training and 'business as usual,' which is putting athletes in a bad position," Han said.

Many athletes' training regimens have, in fact, disintegrated, as gyms, pools and communal workout spaces around the country have been closed. The USOPC has closed its Olympic training centers to all but the 180 or so who live at them — and many in those groups have chosen to leave campus.

Hirshland said it needed to be clear to every elite and recreational athlete out there that "as Americans, the No. 1 priority needs to be health and safety," and not training.

The USOPC has increased availability of mental and emotional counseling, as anxiety builds over what comes next. About 190 of 550 spots on the U.S. team are scheduled to be handed out for gymnastics, swimming and track at Olympic trials in June — all of which are in jeopardy.

Both the IOC and the USOPC leadership have acknowledged the realities of a qualification process that is being altered beyond recognition. Hirshland says the federation is working with individual sports, both at the national and international levels, to adapt in the event the Olympics take place without a traditional qualifying structure.

While Hinchey wrote that the chances for a level playing field were becoming more remote, he did say "our world-class swimmers are always willing to race anyone, anytime and anywhere; however, pressing forward amidst the global health crisis this summer is not the answer."