Nearly seven years after the September 11 attacks, the US Government says it is doing better at securing nuclear and radiological materials.

Not good enough, congressional investigators say.

A report yesterday faulted the Bush Administration for taking too long to ensure such materials do not fall into terrorists' hands.

The Government Accountability Office said requirements to ensure that someone has a legitimate reason to buy or carry radioactive materials are more than three years behind schedule.

In a probe last year, investigators said they set up a bogus company and obtained a licence that allowed them to buy enough radioactive material for a small dirty bomb.

Officials hope the licensing requirements will prevent this from happening again.