Coffee chain Starbucks Corp has asked customers in the United States to leave their guns at home, after being dragged into an increasingly fractious debate over gun rights in the wake of multiple mass shootings.

While many US restaurant chains and retailers do not allow firearms on their properties, Starbucks' policy had been to default to local gun laws, including "open carry" regulations in many US states that allow people to bring guns into stores.

In August, this led gun-rights advocates to hold a national "Starbucks Appreciation Day" to thank the firm for its stance, pulling the company deeper into the fierce political fight.