CONCORD, N.H. — New Hampshire Sen. Jeanne Shaheen has asked the Secret Service and Internal Revenue Service to investigate reports of tax fraud affecting more than 150 doctors and health care providers in the state and in Vermont.

The medical societies in both states say Social Security numbers have been stolen and used to file fraudulent federal tax returns. At least several hospitals and some private providers have been targeted.

Rick Adams, a spokesman for Dartmouth-Hitchcock Medical Center, tells the Valley News about 50 doctors and other employees who work at the hospital have been affected.

Scott Colby of the New Hampshire Medical Society says similar cases have been reported in other states, such as Maine, Connecticut and Massachusetts.

Shaheen is asking for a joint investigation between the Secret service and IRS.

“We must act swiftly to stop any fraudulent activity, bring the perpetrators to justice and ensure that physicians and providers have the information they need to protect themselves,” Shaheen said Wednesday.