Vietnam on Thursday criticized a U.S. State Department award to detained blogger Nguyen Ngoc Nhu Quynh, often referred to by her pen name, "Mother Mushroom".
Quynh, detained in October for anti-state propaganda, was one of 13 women worldwide to receive an International Women of Courage Award. The awards were presented by First Lady Melania Trump on Wednesday.
Foreign ministry spokesman Le Hai Binh said making an award to someone being investigated for breaking Vietnam's law was "not suitable and beneficial to the development of the two countries' relationship".
Vietnam has been keen to establish ties with President Donald Trump's administration.
It stands to lose as much as any country with his decision to pull the United States from the Trans Pacific Partnership free trade agreement.
Vietnam is also in a dispute with China over the East Sea, internationally known as the South China Sea, and strengthened its alliance with the United States under President Barack Obama.
Quynh is known by her pen name of "Me Nam" - which translates as Mother Mushroom.
Police arrested her last year on accusations of abusing democratic rights, distorting facts and going against the government and the Party with her blog and Facebook posts.