Feb. 13 (Bloomberg) — Apple Inc. uncovered labor violations in its supply chain, including the use of underage workers and abuses of migrant laborers lured by recruiters to work in factories making its devices.

Apple conducted 451 reviews of multiple levels in its supply chain covering facilities where nearly 1.5 million people work, according to its eighth annual internal audit. The company said it's more aggressively trying to remove the use of so- called conflict minerals and has gotten 95 percent of the facilities to keep work to below 60 hours per week.

The report reveals the behind-the-scenes work that goes into making the company's gadgets, from the mining of minerals used in components to assembly lines in China where a final product is put together. Apple sold a record 150.3 million iPhones and 71 million iPads in its latest fiscal year, putting pressure on suppliers such as Foxconn Technology Group to manufacture enough devices fast enough to keep up with demand.