Seoul: LG Electronics said Thursday it would "actively respond" to a lawsuit filed by Japan's Sony that seeks to block mobile phone shipments to the United States by the South Korean firm.

Sony has filed a patent infringement complaint claiming LG's mobile phones sold in the United States had used its technologies without permission.

LG, the world's third-largest mobile phone maker, said it would take action after reviewing the technologies.

Spokeswoman Na Joo-Young told AFP: "Based on results of our review, we will take action and actively respond" to Sony's move.

Sony has filed a complaint with the US International Trade Commission - which can ban imports of products found to violate US patents - and also with a federal court in Los Angeles, which has the power to impose fines.

Sony's mobile phone joint venture, Sony Ericsson Mobile Communications, is the world's sixth-largest mobile phone maker. Sony is also the world's third-largest TV maker.

LG's mobile phone business has been under heavy pressure due to its slow response to the fast-growing popularity of smartphones. Chief executive Nam Yong resigned in September after the mobile phone business stumbled.

LG's third-quarter net profit plunged 99 percent year-on-year to 7.57 billion won (6.6 million dollars)