The pressure on the NCAA and professional sports leagues to hold games without fans further escalated Wednesday morning as Anthony Fauci, head of the infectious diseases division at the National Institutes of Health, recommended against large gatherings during a congressional hearing about the coronavirus.

On Tuesday, the Ivy League canceled its conference tournaments and two others conferences — the Big West and the Mid-American Conference — decided to hold their tournaments in mostly empty arenas in Anaheim, Calif. and Cleveland.

Meantime, the NBA’s Golden State Warriors played in front of a crowd Tuesday night in the face of recommendations against doing so from local government and health officials. The NCAA said it would monitor the situation as it allowed the ACC to decide to start its men’s tournament in Greensboro, N.C. with a crowd. The Big East, Big 12 and Big Ten, as of Tuesday, all prepared to start tournaments Wednesday unabated.

“We would recommend that there not be large crowds,” Fauci said, asked by Rep. Glenn Grothman (R-Wis.) whether the Ivy League was overreacting or the NBA was underreacting. “If that means not having any people in the audience when the NBA plays, so be it. But as a public health official, anything that has large crowds is something that would give a risk to spread.”

The NCAA men’s and women’s tournaments, the organizations marquee and most lucrative event, are scheduled to begin next week. The opening games of the tournament, dubbed the First Four, will take place in Dayton, Ohio, where the University of Dayton moved classes online and Gov. Mike DeWine (R) has recommended indoor sporting events be played without crowds.

A Dayton spokeswoman deferred comment to the NCAA, declining to say whether the school had any say in holding the games or keeping out fans.

In the District of Columbia, health officials Wednesday urged the cancellation of all nonessential mass gatherings through the end of the month. That includes conferences, conventions and entertainment events drawing more than 1,000 people