McDonald's Corp. (MCD) is planning to sell its Boston Market casual chicken chain to refocus on hamburgers, the Chicago Tribune reported on Friday.

The newspaper said Boston Market employees had been told on Thursday that McDonald's was going to review its options about continued ownership and planned to sell the chain.

A McDonald's representative was not immediately available for comment.

The Tribune quoted a McDonald's spokesman as saying: "We are beginning to look at potential options and will explore our alternatives during 2007."

McDonald's, the world's largest restaurant company, acquired Boston Market in 1999 for $173.5 million as part of a diversification strategy that included the purchase of controlling interests in Chipotle Mexican Grill Inc. (CMG), which it spun off last year.