UPDATE 2-U.S. warns against inadvertently hiring North Korean IT workers

(Adds detail from advisory)

WASHINGTON, May 16 (Reuters) - U.S. officials have warned businesses against inadvertently hiring IT staff from North Korea, saying that rogue freelancers were taking advantage of remote work opportunities to hide their true identities and earn money for Pyongyang.

In an advisory issued by the State and Treasury departments and the FBI, the United States said the effort was intended to circumvent U.S. and U.N. sanctions, and bring in money for North Korea's nuclear weapons and ballistic missile programs.

"There are thousands of DPRK IT workers both dispatched overseas and located within the DPRK, generating revenue that is remitted back to the North Korean government," the advisory stated.

"These IT workers take advantage of existing demands for specific IT skills, such as software and mobile application development, to obtain freelance employment contracts from clients around the world, including in North America, Europe, and East Asia," the advisory said.

Many North Korean workers pretended to be from South Korea, Japan, or other Asian countries, the advisory said. It laid out a series of red flags that employers should watch for, including a refusal to participate in video calls and requests to receive payments in virtual currency.

U.S. officials said the North Koreans were mostly based in China and Russia, with smaller numbers operating out of Africa and Southeast Asia. Much of the money they earn is taken by the North Korean government, they said.

The officials also said that companies who hired and paid such workers may be exposing themselves to legal consequences for sanctions violations. (Reporting by Paul Grant and Raphael Satter; Editing by Tim Ahmann and Sandra Maler)