The Food and Drug Administration said on Thursday it will detain imports of Chinese farm-raised catfish, shrimp and other seafood to make sure the shipments are free from harmful residues.

"We're taking this strong step because of current and continuing evidence that certain Chinese aquaculture products imported into the United States contain illegal substances that are not permitted in seafood sold in the United States," said Dr. David Acheson, FDA's assistant commissioner for food protection.