A federal panel on Monday rejected a recommendation that states use only voting machines whose results could be independently verified.

A committee of the National Institute of Standards and Technology voted 6-6 not to adopt the recommendation by the agency's staff, who warned in a report released last week that the paperless electronic voting machines are vulnerable to errors and fraud and cannot be made secure. Eight votes are required to pass a measure.

However, members of a NIST advisory panel said requiring voting systems that use paper or have independent audit trails could further strain state election officials who already have their own testing and security measures in place.

The panel was created by Congress after vote-counting problems in the 2000 presidential election to advise the federal Election Assistance Commission.

Some panel members worried the systems with audit trails could present problems of their own, including printer errors. Others said it was unclear that paper records could be used by voters who are blind or have other disabilities.

But a computer scientist on the panel warned his colleagues that software errors in the paperless machines could go undetected without a way of verifying the voting results.

That could lead to a scenario where you have "got an election result that is wrong and you have no evidence to show that it's wrong," said Ronald Rivest, a professor at the Massachusetts Institute of Technology.

The paperless voting machines are essentially laptop computers that allow voters to cast their ballots by touching a screen, and then tally the results. They are widely used across the country.

The NIST panel is drafting recommendations for the election commission, which will then issue its own set of recommendations to state voting boards. Those recommendations will not be binding but are followed by many states.