SAN FRANCISCO – The nation's largest tobacco company is suing the city of San Francisco over a law that would ban the sale of cigarettes and other tobacco products at pharmacies in the city.

Philip Morris USA filed suit in federal court Wednesday, claiming that the new law is unconstitutional.

San Francisco passed the ban in July, saying people getting their prescriptions filled shouldn't be offered the opportunity to buy tobacco products.

The new law is scheduled to go in effect on Oct. 1.

The suit by Philip Morris comes after Walgreens also filed suit in Superior Court earlier this month seeking an emergency injunction to block the ban.

Both sides in that case are due in court Sept. 30.

Information from: San Francisco Chronicle, www.sfgate.com/chronicle