Hackers have allegedly demanded an estimated Rs 200 crore in cryptocurrency from the All India Institute of Medical Sciences (AIIMS), Delhi, as its server remained out of order for the sixth day, official sources said on Monday.

It is feared that data of around 3-4 crore patients could have been compromised due to the breach detected Wednesday morning. Patient care services in emergency, outpatient, inpatient and laboratory wings are being managed manually as the server remained down, the sources said.