Staples Inc. unveiled plans Tuesday aimed at turning around the company by closing US and international stores, reducing the size of existing locations, restructuring its overseas business, and shaking up leadership.

The Framingham-based office supply chain said it would trim the total amount of retail space in North America by about 15 percent by the end of 2015. That effort will include shutting 30 stores and downsizing another 30 during fiscal year 2012. Staples has about 1,900 stores in North America.