SEOUL: Samsung Electronics flagged a leap of nearly 60 percent in third-quarter operating profits Thursday, as its mobile and chip business were boosted by US sanctions against its Chinese rival Huawei.

The South Korean tech giant said in an earnings estimate that it expected operating profit to reach 12.3 trillion won ($10.6 billion) for July to September, up from 7.8 trillion won in the same period last year.

The prediction would represent the firm's biggest operating profit of any quarter for two years and was also ahead of analyst forecasts.

Samsung Electronics is crucial to South Korea's economic health. It is the flagship subsidiary of the giant Samsung group, by far the largest of the family-controlled conglomerates known as chaebols that dominate business in the world's 12th-largest economy.

Its overall turnover is equivalent to a fifth of the country's gross domestic product.

Despite the optimistic forecast, Samsung Electronics shares closed down 0.3 percent on Thursday.

Shares in LG Electronics, South Korea's second-largest appliance firm after Samsung, also closed lower Thursday, down 2.9 percent, despite forecasting third-quarter operating profits would jump 22.7 percent on-year to 959 billion won, a record for any quarter.

Samsung withholds net profit and sector-by-sector business performance data until it releases its final earnings report, expected later this month.

Adding to the company's challenges, vice-chairman and de facto leader Lee Jae-yong is being retried over a sprawling corruption scandal that could see him return to prison. He is not being held in custody during the proceedings, but a guilty verdict could deprive the firm of its top decision-maker.