Kingsport police say that about 2:45 a.m. two men entered the Chevron at 220 Carolina Pottery Drive.
One suspect carried a small black handgun. He was wearing a black hooded sweatshirt and a clown mask with green hair, red lips and a white face. The other suspect wore a dark-colored American Eagle sweatshirt and a mask that looked like a baseball with seams and eyes.
Police say the men forced the female clerk to open the registers behind the counter. They then placed money into a bag and fled the scene.
A second robbery occurred about 6:20 p.m. at the Roadrunner on South Wilcox Drive.
Police say a white male wearing blue jeans, a white T-shirt, black jacket and light-colored cap approached the counter. He lifted his shirt to display the handle of a handgun, then demanded money from the register. He left the store with an undetermined amount of cash.
Police have not determined if this suspect was involved in the earlier robbery. Anyone with information on the suspects is asked to call Central Dispatch at 246-9111 or the Kingsport Police Department Criminal Investigations Division at 229-9429.