McDonald’s Korea has ended sales of its Chungju Glutinous Corn Cheese Croquette Burger ahead of schedule after customers reported finding foreign objects in the product.

The limited-time burger, released on July 9 as part of the fifth anniversary of the company’s “Taste of Korea” project, was originally scheduled to remain on sale until August 12.

However, sales at restaurants nationwide ended at 8 p.m. on July 30.

The burger had proven popular, surpassing 1 million units sold within two weeks of its launch.

The early withdrawal followed multiple customer complaints claiming they had bitten into small stone-like particles while eating the burger.

McDonald’s Korea said it has a policy of suspending sales when three or more similar reports are received.

The company said it has no plans to resume sales at this time and is investigating the cause of the contamination with the farm that supplied the ingredients and other suppliers involved in the production process.