Apple, under attack for poor labor practices at its Asian contract manufacturers, said it had asked the Fair Labor Association to inspect them.

We believe that workers everywhere have the right to a safe and fair work environment, CEO Tim Cook said. The Cupertino, Calif.-based Apple, the world's most valuable company, made the announcement on its Web site Monday.

Shortly afterwards, shares of Apple set an all-time record of $503.83, valuing the company at $468 billion.

Under Cook, a supply chain management expert and late Chairman Steve Jobs, Apple shifted all its manufacturing away from U.S.-based contract manufacturers, handing off most to Taiwan's Hon Hai Precision Industries, known as Foxconn.

Hon Hai has as many as 700,000 workers in mainland China and received publicity in 2010 and 2011 after a series of suicides, accidents and other incidents at its factories.

Apple said it has asked the Fair Labor Association to audit operations in Shenzen and Chengdu. Cook said the inspections are unprecedented in the electronics industry.

Further inspections will be made at factories of Quanta Computer, another prime vendor to Apple as well as Amazon for the Kindle and Kindle Fire series of tablets. Chinese maker Pegatron will also be audited.

Apple, whose board of directors includes former U.S. Vice President and Nobel Peace Laureate Al Gore, has been under fire from labor groups and users, including SumofUs, which delivered a petition demanding labor audits with 250,000 signatures, last week to the company.

Apple's annual meeting, scheduled for Feb. 23, may feature shareholder demands for auditing of labor practices.