Forever 21's U.S. operator on Sunday filed for bankruptcy for the second time in six years and said it would wind down operations in the country, hurt by mounting online competition in the fast-fashion sector and weak mall traffic.

F21 OpCo, LLC, the company and licensee of the brand in the U.S., filed a Chapter 11 case in the U.S. Bankruptcy Court for the District of Delaware. Although stores will remain open for now, Forever 21, which is headquartered in Los Angeles, said it will hold liquidation sales at its U.S. stores.

Forever 21 is shutting down after filing for bankruptcy, citing intense competition from global fast-fashion brands.

Forever 21's U.S. retail operator plans liquidation sales after filing Chapter 11 for the second time in six years.

Fast-fashion retailer Forever 21 has filed for Chapter 11 for a second time. It will wind down US operations unless it can find a buyer.