The U.S. government has tightened restrictions on the use of ethanol in hand sanitizers, citing safety concerns, according to documents seen by Reuters.

The move has forced some suppliers to halt sales at a time of high demand as the country is battling the COVID-19 pandemic.

The U.S. government is keen to protect consumers from potentially dangerous impurities in hand sanitizer.

Sanitizers are at the forefront in the battle against COVID-19, having been recommended alongside soaps.

The U.S. Food and Drug Administration (FDA) on April 15 issued limits on certain chemicals permitted in alcohol-based hand sanitizer, updating temporary guidance it adopted last month as the health crisis deepened and more manufacturers registered to produce hand sanitizer.

Reuters reports an unnamed source to say that after the FDA imposed the restrictions, it notified several ethanol companies that their product does not meet safety standards, forcing them to halt production and cancel supply agreements.

The agency said in a statement it was committed to "working with manufacturers, compounders, state boards of pharmacy and the public to increase the supply of alcohol-based hand sanitizer available to Americans."