New York Blood Center (NYBC), one of the largest nonprofit blood centers in the United States, says it is experiencing service disruptions after being hit by a ransomware attack. 

NYBC said in a statement on Wednesday that the organization detected suspicious activity on its IT systems on January 26, which it has since confirmed was a ransomware attack. 

“We took immediate steps to help contain the threat, including taking certain systems offline,” NYBC said in the statement. 

NYBC, which provides blood to over 200 hospitals in the northeast U.S. and transfusion-related medical services to over 500 hospitals nationally, warned that the incident has caused operational disruption. The nonprofit said that donation center activities and blood drives may need to be rescheduled, and that processing times for blood donations “may be longer than normal.” 

The organization said it is working to restore its systems as quickly and as quickly as possible but noted that “at this time, we do not have a specific timetable for system restoration.”

This comes as the NYBC declared a blood emergency last week after seeing a 30% drop in donations that the organization says has “crippled the region’s blood supply.” Donations of all blood types are urgently needed, with some types “dangerously low” supply, NYBC said in a press release at the time. 

“We understand the critical nature of our services, and the health of our communities remains our top priority,” the blood center said in Wednesday’s statement. “We remain in direct communication with our hospital partners and are implementing workarounds to help restore services and fulfill orders.” 

It’s not yet known who was behind the cyberattack and no major ransomware group has yet claimed credit for the intrusion. It’s also unclear whether any patient data was accessed as a result of the attack, or whether NYBC received a ransom demand. NYBC did not immediately respond to TechCrunch’s questions.