UPDATE 1-Trump administration adds China's SMIC and CNOOC to Defense blacklist

(Adds background, requests for comment)

WASHINGTON, Dec 3 (Reuters) - The Trump administration on Thursday added China's top chipmaker SMIC and oil giant CNOOC to a blacklist of alleged Chinese military companies, a move likely to escalate tensions with Beijing before President-elect Joe Biden takes office.

The Department of Defense designated a total of four additional companies as owned or controlled by the Chinese military, including China Construction Technology Co Ltd and China International Engineering Consulting Corp.

The move, which was first reported by Reuters on Sunday, brings the total number of companies blacklisted to 35. While the list did not initially trigger any penalties, a recent executive order issued by President Donald Trump will prevent U.S. investors from buying securities of the blacklisted firms starting late next year.

The Chinese Embassy in Washington, Semiconductor Manufacturing International Corp (SMIC) and China National Offshore Oil Corp (CNOOC) did not immediately respond to requests for comment. (Reporting by Alexandra Alper and Humeyra Pamuk Editing by Chris Reese and Diane Craft)