LOUISVILLE - KFC says it's popcorn chicken had a bit more heat than intended.

The fried chicken giant is suing one of it's suppliers, saying the cups used to hold popcorn chicken caught on fire while being reheated in the microwave oven.

Louisville-based KFC said in a federal lawsuit that Paris Packaging Inc. of Paris, Texas, changed the content of the ink used on the containers, using a new formula that includes carbon, which may catch fire if heated.

The restaurant chain said at least two people reported fires. KFC said company employees then tested the cups in a microwave oven and, after being heated for 13-19 seconds, the cups caught fire.

KFC spokesman Rick Maynard said no one was injured because of the fires.

"Since the safety of our customers is our top priority, KFC took immediate action by removing the packaging based on two reported issues," Maynard said.

KFC, a division of fast food giant Yum Brands, is seeking at least...