WASHINGTON (AP) — There's no guarantee President Barack Obama's health care law will launch smoothly and on time, congressional investigators say in the first in-depth independent look at its progress.

But in a report released Wednesday, the congressional Government Accountability Office also sees positive signs as the Oct. 1 deadline approaches for new health insurance markets called exchanges to open in each state — in many cases over the objections of Republican governors.

Additionally, the report discloses that the administration had spent nearly $400 million as of March to set up the infrastructure of a sprawling system involving major federal agencies, every state, hundreds of insurance companies, and millions of citizens, among them many individuals seeking coverage for the first time.