He would meet leaders in both countries "to reaffirm the strength of our bilateral relationships," it tweeted on Thursday.
Vietnam's Ministry of Foreign Affairs spokeswomen Le Thi Thu Hang said at a press meet the same day that O'Brien will be in Vietnam from Friday to Sunday for high-level meetings to discuss bilateral relations and regional and international issues that concern both Vietnam and the U.S.
Two weeks ago U.S. Secretary of State Mike Pompeo visited Hanoi where he affirmed his nation’s continued support for a strong, prosperous and independent Vietnam.
O'Brien, 54, participated in last week’s virtual ASEAN - U.S. Summit organized by Vietnam, highly appreciating Vietnam's role as the chair of ASEAN this year, particularly in coordinating regional efforts at a time full of difficulties and challenges such as the Covid-19 outbreak.
He is the fourth person to hold the national security advisor position during the presidency of Donald Trump.
Vietnam and the U.S. have been marking the 25th anniversary of the normalization of ties in 1995, 20 years after the end of the Vietnam War.
They are comprehensive partners today, with bilateral trade increasing from $450 million in 1994 to $77 billion last year.