The Trump administration is waiving entrance fees at national parks, encouraging Americans to get outside during a time when most indoor gatherings are curtailed because of fears of the spread of the coronavirus.

“This small step makes it a little easier for the American public to enjoy the outdoors in our incredible national parks,” Interior Secretary David Bernhardt said in a statement Wednesday.

But the Coalition to Protect America’s National Parks, a group of current and former park employees and volunteers, questioned whether that would cause crowding at a time when public health experts are urging Americans to stay six feet apart and President Trump has requested that gatherings are limited to no more than 10 people to slow the spread of the pandemic.

“We understand the reasons behind this decision,” Phil Francis, chair of the coalition, said in a statement Thursday. “But these are not normal circumstances. … It is irresponsible to urge people to visit national park sites when gathering at other public spaces is no longer considered safe. We are concerned that the Secretary’s decision to waive entrance fees will lead to overcrowding and a greater risk to the health and well-being of our NPS employees and visitors.”

The move comes just days after Bernhardt closed some of the most iconic sites in the parks system at the suggestion of public health officials in the park system, an Interior spokesman said. Over the weekend and on Monday, the Statue of Liberty National Monument and Ellis Island, Washington Monument and the Gold State Recreation Area were closed to the public during the outbreak, but the vast majority of more than 400 sites remain open.