Seoul, Nov 22 (IANS): The recent restriction on South Korean chipmaker SK hynix plan by the US to bring advanced equipment to a Chinese factory was made out of "legitimate concerns," and more such moves could be possible, Washington's top trade official has said.

US Trade Representative (USTR) Katherine Tai made the remarks in her recent radio interview with CBS, a Seoul-based broadcaster, which aired on Monday.

"I am aware that the technology in question is highly sensitive, and that there are legitimate concerns about the risks to national security in terms of where this technology ends up," Tai said.

SK hynix had planned to install some of the new extreme ultraviolet lithography (EUV) machines by Dutch firm ASML, to its factory in Wuxi, China, to renovate its factory and to produce memory chips more efficiently, reports Yonhap news agency.

But Washington has barred it from shipping the equipment to China amid an intensified Sino-U.S. rivalry, according to officials.

"It is important for us to work with our partners and our allies in particular, on matters of shared economic and national security. And I also want to acknowledge that we consider Korea to be one of our most important national security partners," Tai added.

Asked if any other items could also come under such regulations down the road, Tai said, "Yes when it comes to matters of national security. National security includes military and defense concerns, but it can also be broader."

Earlier in the day, SK hynix CEO Lee Seok-hee said his company will respond to the issue "wisely while cooperating with interested parties."

In September, Washington asked major chipmakers and automakers to share business information, and Samsung Electronics and SK hynix submitted their business information earlier this month.