A pilot program for such a verification system is to begin this year with 10 employers in 10 cities.

An elaborate verification system will be put into effect, involving on-site inspection for the first time.

The program is seen as the precursor for a verification system that would become mandatory with comprehensive immigration reform.

But American officials say that verification system, put in place a few months ago to deal with the sanctions violations, has already broken down.

"Ultimately, we have to have a verification system that deals with all people who are working."

In addition, this verification system can provide a model which may be incorporated into future agreements.

The scientists cautioned that no verification system can be perfect.

At the same time, there must be a reliable verification system.

One barrier to this is the double verification system.

We need to have a more balanced approach than just a verification system.