China has returned 887,000 tonnes of U.S. corn shipments tainted with a genetically-modified (GM) strain not approved by the country's agriculture ministry since last October.

These corn shipments were found to contain the unapproved MIR162, a strain of insect-resistent transgenic corn, according to the General Administration of Quality Supervision, Inspection and Quarantine.

China detected the first batch of MIR162 tainted corn shipment from the U.S. in last October in Shenzhen, and found several batches at the country's different ports after that.

The administration urged local entry-exit inspection and quarantine bureaus to step up detection of the imported farm produce and return or destroy those tainted with unapproved GM components.