A judge in San Francisco late Tuesday ordered Samsung Electronics Co. to halt sales of its Galaxy 10.1 tablet computer while the court considers Apple's claim the South Korean tech giant illegally copied the design of the popular iPad.

U.S. District Judge Lucy Koh said Apple Inc.'s lawsuit appeared likely to prevail.

"Apple has established a strong case on the merits," Koh said.

Koh had earlier said the two products are "virtually indistinguishable," but she declined in December to take the dramatic step of prohibiting sales of the Galaxy 10.1. She changed her mind after the U.S. Court of Appeals for the Federal Circuit told Koh to take another look at Apple's request for an injunction, ruling June 19 that it appeared the Cupertino-based company had a strong case. The Washington, D.C., court handles most patent appeals.

"Although Samsung has a right to compete, it does not have a right to compete unfairly, by flooding the market with infringing products," Koh wrote in her Tuesday order. She said Apple would be "irreparably harmed" if sales of the Galaxy 10.1 continued.

Long-running patent fight

Samsung said it was disappointed with the court's decision.

"We will take necessary legal steps and do not expect the ruling to have a significant impact on our business operations, as we possess a diverse range of Galaxy Tab products," it said in a statement.

Koh ordered Apple to post a $2.6 million bond in case it ultimately loses the case.

The ruling is a small part of a much larger patent battle between the two tech giants, who are scheduled to go to trial next month in San Jose.

Apple filed its lawsuit last year, and the two companies are enmeshed in patent disputes around the globe revolving around smartphones and handheld computers. Samsung, with its Android-powered products, has emerged as one of Apple's chief rivals.

Apple also accuses the South Korean company of infringing patents related to the iPhone. Apple is seeking a similar injunction barring Samsung from selling one of its smartphones in the United States.