Authorities in Vietnam are investigating "an incident" involving the organizer of an upcoming concert by K-pop group Blackpink, the government said on Wednesday.

Blackpink is scheduled to perform two shows in Hanoi this month as part of its Born Pink world tour.

What is the problem for Blackpink in Vietnam?

Earlier this week, reports surfaced on social media that a map on the website of concert organizer iME Entertainment resembled the so-called "nine-dash line" that China uses to demarcate its claims in the South China Sea.

Vietnam and other neighboring countries contest China's claims.

According to Vietnam-based journalist Tung Ngo, the labels on the map appear to show different countries where iME entertainment has local operations.

Vietnam's Culture Ministry said late on Wednesday that it had ordered an inspection of the website "to verify the suspicion that the company organizing the Blackpink music night promoted the cow-tongue line," using Hanoi's term for the map marking.

On Thursday, Foreign Ministry spokesperson Pham Thu Hang said she was "aware that relevant authorities were trying to clarify these claims."

The Vietnam leg of Blackpink's world tour had become a "hot-button issue," she added.

The public uproar follows a decision made earlier this week by Vietnam's film review board to ban the upcoming "Barbie" film for allegedly depicting the same "nine-dash line."

Vietnamese Blackpink fans threaten boycott

After claims about the organizer's website emerged on social media, some Vietnamese Blackpink fans demanded a boycott of the concerts.

"In support of Vietnam, we'd better... not attend entertainment shows organised by iME," read a comment posted on the Blackpink Vietnam FC (fan club) Facebook page.

Another user said: "This concerns the territorial claim of a country. Although I like Blackpink, we should raise our voice."

Some users said they had purchased tickets for the upcoming shows but would no longer attend.

"Bought two tickets for me and my date. Then saw the cow-tongue, and quit," another user posted. "I am (a) patriot."

The iME Entertainment website was listed as being "under maintenance" on Thursday.