Sony Corp. filed patent-infringement claims seeking to block LG Electronics Inc. from shipping mobile phones to the U.S.

Sony filed the complaints Tuesday with the U.S. International Trade Commission in Washington and in a federal court in Los Angeles. The ITC, which is considering at least a dozen cases related to the expanding market for smart phones, has the power to block imports of products found to violate U.S. patents. The federal court can impose financial penalties.

LG phones, including the Lotus Elite, Neon, Remarq, Rumor 2 and Xenon, are using Sony technology without permission, Sony said in the civil lawsuit.

LG, the world's third-largest maker of mobile phones, is also being targeted in Sony's patent suit for its Blu-ray disc players. A copy of the ITC complaint wasn't immediately available.

"Sony has been keen to protect its patents," said Yuji Fujimori, an analyst at Barclays Capital. "U.S. is an important market for Sony as its mobile phone venture with Ericsson is trying to win a bigger share."

The eight Sony patents in the federal court case include ones related to a way to display telephone-number listings, direction keys on a portable phone and signal transmission.

John Taylor, a spokesman in the U.S. for Seoul-based LG, said the company doesn't comment on pending litigation.

Sony plans to invest ¥100 billion over the next fiscal year to double production capacity for image sensors used in smart phones.

LG, which plans to begin sales in January of the first smart phone built with a dual-core processor, said Monday it is trying to boost revenue at its consumer electronics, displays and handset units by 13 percent in 2011.