WASHINGTON (AP) — Congress will hear testimony Wednesday detailing how undercover investigators used fake identities to get taxpayer-subsidized health insurance under President Barack Obama's law.

The nonpartisan Government Accountability Office says its undercover operatives were able to get subsidized health care in 11 out of 18 attempts. The GAO is still paying premiums for the policies, even as the Obama administration attempts to verify phony documentation.

The GAO will deliver its findings at a House Ways and Means Committee hearing. An advance copy of the agency's testimony was provided to The Associated Press.

The administration says it will review the testimony carefully and work with GAO to strengthen safeguards.