A report from the investigative arm of the U.S. Congress says a new tracking system is needed to see if economic sanctions against Iran are effective.

The Government Accountability Office, GAO, says several U.S. agencies need to measure if sanctions are helping to curtail Iran's alleged support of terrorist groups.

The report says the agencies also need to assess the status of Iran's controversial nuclear program.

The United States imposed economic sanctions on Iran in 1987, but this new report from the GAO says the impact of those long running sanctions is difficult to determine. 

The report comes as President Bush completes a visit to the Middle East aimed, in part, at securing support for increased pressure on Iran. 

Some information for this report was provided by Reuters.