The agency did not identify the specific drug that was impacted but said in an announcement Thursday the shortage was due to a key ingredient sourced from China being unavailable.

“A manufacturer has alerted us to a shortage of a human drug that was recently added to the drug shortages list,” the FDA said. “The manufacturer just notified us that this shortage is related to a site affected by coronavirus. The shortage is due to an issue with manufacturing of an active pharmaceutical ingredient used in the drug.”

While the FDA hasn’t named the drug, it did stress that there are alternatives patients can use in its stead. The agency is working with other manufacturers to help fill the shortage with increased availability of those other options.

While this is the first U.S. shortage due to the COVID-19 outbreak, it likely won’t be the last. The FDA has identified 20 drugs that either source their active ingredients or receive their finished drug products from China. (None are considered critical drugs.)

So far, no other pharmaceutical companies have reported shortages, but continued slowdowns in Chinese factories as the country tries to contain the outbreak could change that.

More must-read stories from Fortune:

—Trump budget cuts could become a big problem as coronavirus spreads
—China cracking down on VPNs in coronavirus crisis
—China tries to restart economy as outbreak slows. Is it heading back to work too soon?
—5 reasons coronavirus statistics seem inconsistent
—Coronavirus may be the straw that breaks the back of oil fracking

Subscribe to Fortune’s Brainstorm Health newsletter for daily updates on biopharma and health care.