US coffee shop giant  Starbucks is to close some 600 'underperforming' company-operated stores in the US market as part of a reorganisation to pump up profitability.

'This decision is a result of a rigorous evaluation of the US company-operated store portfolio and includes the 100 stores targeted for closure in the company's previously announced plans,'  the Seattle-based company said in a statement.

Starbucks also said it expects to open fewer than 200 new US  company-operated stores in fiscal 2009.

The company said that full-time and part-time retail positions 'will be eliminated,' but many employees will be able to take available positions at nearby Starbucks stores.