The Delhi Police's Intelligence Fusion and Strategic Operations unit has written to CBI seeking details from Interpol about the IP addresses of email IDs from China and Hong Kong in connection with its probe into the AIIMS server attack case, officials said on Sunday.

The Central Bureau of Investigation (CBI) is India's nodal agency for Interpol matters.

According to sources, the attack on the servers of AIIMS-Delhi is suspected to have originated from locations in China and Hong Kong. Further details have been sought which can be obtained from companies in China and Hong Kong.

The All India Institute of Medical Sciences, Delhi faced the cyber attack on November 23, paralysing its servers. A case of extortion and cyber terrorism was registered by the Intelligence Fusion and Strategic Operations (IFSO) unit of the Delhi Police on November 25.

Internet services were blocked as per the recommendations of the investigating agencies. The Computer Emergency Response Team (CERT-In), Delhi cybercrime special cell, Indian Cybercrime Coordination Centre, Intelligence Bureau, CBI and National Investigation Agency, are investigating the incident.

The attack affected the hospital's outpatient and inpatient digital services, including smart laboratory, billing, report generation and the appointment system.