WASHINGTON — The labor group hired by Apple Inc. to assess working conditions at three manufacturing plants in China said Tuesday that the improvements it recommended in March are being implemented ahead of schedule.

The Fair Labor Association said in a progress report that Apple Inc.’s largest supplier, Foxconn, had made all 195 improvements to working conditions that were due by the end of May. Foxconn also completed 89 of the 165 improvements due by next July.

The review of working conditions follows a rash of suicides at Foxconn facilities – about a dozen since 2010 – and an explosion at the iPad-making plant in Chengdu in May 2011 that killed four workers. The explosion was caused by the build-up of aluminum dust, and the FLA said in March that Foxconn had already improved operating procedures to reduce the risk of a recurrence.

Among the changes enacted since then, the FLA said that Foxconn had reduced work hours to 60 hours per week.