Starbucks CEO Howard Schultz is asking customers to no longer bring guns into his company's coffee shops or outdoor seating areas. 

Schultz, in an open letter to be published tomorrow in newspapers including the "New York Times" and the "Wall Street Journal," says Starbucks stores have been "thrust unwillingly" into the middle of the gun-control debate with more customers bringing firearms into stores during so-called "Starbucks Appreciation Days."  

Schultz says the "open carry" debate has become "increasingly uncivil and, in some cases, even threatening." He says while he's asking customers not to bring guns into Starbucks locations, even in states where open-carry is permitted, the stores will continue to serve customers who do.