The Red Cross declared Tuesday an unprecedented blood shortage in the U.S. that it calls the worst “in over a decade” amid rising Omicron cases.

“The American Red Cross is facing a national blood crisis,” the organization said in a press release. “Its worst blood shortage in over a decade, posing a concerning risk to patient care.” The Red Cross noted that doctors across the country are being forced to make “difficult decisions” regarding patient care, with physicians being forced to choose which patients should receive treatment and which must wait for additional resources. (RELATED: Trials Begin For Blood Test That Claims To Detect Up To 50 Types Of Cancer)

The Red Cross also noted a 10% decrease in blood donations since the beginning of the COVID-10 pandemic. Blood drive cancellations and staffing limitations have also contributed to the overall decrease in the Red Cross’s blood supply, according to the organization.

The Red Cross urged all Americans to donate blood, as “all types are needed, especially types O positive and O negative.” The Red Cross also requests platelet donations in order to prevent delays in “vital medical treatments.”

The Red Cross is responsible for 40% of the nation’s blood supply but has been forced to limit its distribution due to shortages. The organization noted that, as blood cannot be stockpiled or manufactured, that they must rely on volunteer donations.

“Every community in America needs blood on a daily basis. At a time when many businesses and organizations across the country are experiencing pandemic challenges – the Red Cross is no different,” said chief medical officer of the Red Cross, Dr. Pampee Young. “And while we are all learning how to live in this new environment, how we spend our time, where we work, how we give back, how we make a difference in the lives of others – donating blood must continue to be part of it.”