The Federal Bureau of Investigation and National White Collar Crime Center are investigating ongoing attacks against telephone systems operated by public sector entities, including some hospitals. The telephony denial-of-service attacks, which are part of an extortion scheme, start with a phone call to an organization from an individual claiming to represent a collections company for payday loans. The caller usually has a strong accent and asks to speak with a current or former employee concerning an outstanding debt. Failing to get payment from an individual or organization, the perpetrator inundates the targeted telephone network with a continuous stream of calls for an unspecified but lengthy period of time, which can prevent incoming and outgoing calls from being completed. The Association of Public-Safety Communications Officials has published a checklist to help organizations plan for and respond to such attacks, which should be reported to the Internet Crime Complaint Center at http://www.ic3.gov. Because the attacks have targeted numerous hospitals and public health entities, the departments of Health and Human Services and Homeland Security also have become involved in the federal response.