Hospitals are taking strict measures to prevent cyberattacks after federal agencies recently warned they have been targeted by ransomware.

Medical centers across the country are doing everything from disabling their email systems to backing up patient data in preparation for ransomware attacks.

The U.S. Cybersecurity and Infrastructure Security Agency has issued a warning about ransomware activity targeting healthcare institutions. Criminals are targeting hospitals because they are more likely to pay ransoms than other types of institutions, observers say.

“Given the risk of networks being down for hours or even days, hospitals simply cannot afford the time it would take to recover if they didn't pay the ransom,” Justin Fier, director of cyber intelligence and analytics at cybersecurity firm Darktrace, said in an email interview.