Miss USA Sarah Rose Summers has come under fire for mocking Miss Cambodia and Miss Vietnam on social media.

Miss USA Sarah Rose Summers. (Photo: Facebook/Miss USA)

In an Instagram Live video that the 24-year-old posted, she was seen with Miss Colombia Valeria Morales and Miss Australia Francesca Hung. Summers asked her fellow contestants what they thought about Miss Vietnam H'Hen Nie, to which they chorused “fashion!”.

Summers then said: “She pretends to know so much English and after having a conversation and you ask her a question, after having a whole conversation with her, and she goes..." She then appeared to mimic Nie smiling and nodding her head, and laughed before saying "she's adorable".

Miss USA also commented on Miss Cambodia Rern Sinat, saying: “Miss Cambodia is here and doesn't speak any English and not a single other person speaks her language. Can you imagine? Francesca said, 'That will be so isolating', and I said, 'Yes, and just confusing all the time’.”

“Poor Cambodia,” she added.

Miss Vietnam H'Hen Nie and Miss USA Sarah Rose Summers in their national costumes.

After the backlash for her social media behaviour, Summers posted an apology on Instagram on Friday (Dec 14).

“@MissUniverse is an opportunity for women from around the world to learn about each other's cultures, life experiences, and views. We all come from different backgrounds and can grow alongside one another," Summers wrote alongside a photo of the group of women hugging.

"In a moment where I intended to admire the courage of a few of my sisters, I said something that I now realize can be perceived as not respectful, and I apologize.”

The long Instagram post continued: "My life, friendships, and career revolve around me being a compassionate and empathetic woman. I would never intend to hurt another. I am grateful for opportunities to speak with Nat, Miss Cambodia, and H'Hen, Miss Vietnam, directly about this experience. These are the moments that matter most to me."

Screenshop of Miss USA's tweet.

H’Hen Nie also posted the same picture of the women in a group hug and the words: “We all did the great job on the stage tonight! Sleep well and tomorrow will be brighter, my girls. Hugs and kisses. We are a family #MissUniverse #Sisterhood."

Hung and Morales have not responded to the matter, according to CNN Philippines.

Sarah Rose Summers, 24, was recently crowned Miss USA 2018. She is one of the favourites for the pageant crown./.

VNF/CNA