Apple has admitted that children have been used to build iPhones. Nearly a dozen underage teens were working for Apple-contracted facilities in 2009, the company has revealed. The news was posted in a report on Apple's website called Supplier Responsibility.

The underage workers, Apple said, were at three different suppliers' facilities. Though the specific locations aren't disclosed, the report says inspectors visited facilities in China, the Czech Republic, Malaysia, the Philippines, Singapore, South Korea, Taiwan, Thailand, and the United States. The factories in question built iPhones, iPods, and various Apple computers. 

"Across the three facilities, our auditors found records of 11 workers who had been hired prior to reaching the legal age, although the workers were no longer underage or no longer in active employment at the time of our audit," the report says.

The legal age in the facilities' countries, according to Apple's report, is 16. The workers in question were only 15 when they were hired.

The Apple production problems don't end there: More than 60 different facilities were also overworking their employees, Apple says. Apple's code requires suppliers to work employees no more than 60 hours a week with "at least one day a rest per seven days of work."

Beyond that, Apple's audit found two dozen facilities that were paying their people less than the minimum required wage and another 57 that were cheating workers out of legally required benefits - things like sick time and maternity leave. Some factories even cut workers' wages for "disciplinary purposes," according to Apple's report.

Apple says it's requiring the suppliers to develop new measures to correct the violations.

Some of the measures include repaying workers who were underpaid and implementing new systems to ensure correct payment and weekly work-time in the future. The company promises to follow up with the factories to be certain they've taken the appropriate steps.

You can read Apple's full report (PDF) here.