Three Maryland Democrats urged the Trump administration Monday to reverse a directive that has frozen some operations at the National Institutes of Health, saying they have “grave concerns” about the effect on the nearly $50 billion agency’s medical research and other operations.

“Without quick corrective action, the consequences of further disruption could be disastrous for both medical progress in America and our nation’s overall standing and competitiveness on the world stage,” Rep. Jamie Raskin, Sen. Chris Van Hollen and Sen. Angela Alsobrooks wrote in a letter sent to Dorothy Fink, the acting secretary of the Department of Health and Human Services, and shared with The Washington Post.

The new Trump administration has faced widespread complaints since its freeze on health agencies’ external communications took effect last week. Health-care researchers say they have been unable to discuss issuing grants, provide updates on urgent health issues or hold essential meetings. The Trump administration also indefinitely halted staff travel at the agencies.

Trump officials have defended the pause as a necessary part of the presidential transition. They have said there is a process that allows health-care personnel to receive approval from political appointees to share urgent updates.

In their letter, the Democrats called on Fink to “restore full operations at NIH,” including federal advisory committees and staff travel. They also urged HHS to lift its freeze on external communications, which is set to run through Saturday.

The NIH is the largest public funder of biomedical research in the world.