A hacker group from China on Sunday reiterated it is neither admitting nor accepting media reports that it had attacked the computer systems of several major airports and two websites in Vietnam in support of China's sovereignty over the South China Sea.

On Friday afternoon, some flight information screens at both Noi Bai International Airport in Hanoi and Tan Son Nhat International Airport in Ho Chi Minh City have been compromised to display offensive messages toward Vietnam and the Philippines, Vietnam Tuoi Tre News reported Friday.

The airports were forced to shut down their computer systems and switch to manual operations, which led to flights delays, said the report.

The websites of Vietnam Airlines and the Vietnam Football Federation were also hacked, the newspaper said.

Video uploaded on YouTube showed messages saying "China's territorial inviolability," "Vietnam, the Philippines, only the United States, Japan restrict China's pawn" and "a warning from China 1937CN team" appeared on the screens and websites.

The newspaper said that the data of about 411,000 of the airline company's VIP customers was reportedly leaked and uploaded on the Internet.

1937CN team founder Liu Yongfa on Sunday reiterated his team's stance of neither admitting nor deny the attacks.

He told the Global Times that "1937CN is a non-government organization. We do not want to be a victim of the politics."

"At a time when the definition of a cyber crime remains vague in China, our team will start a cyber war to defend the country and the people when their sovereignty and rights are violated by foreign countries," Liu said.

Founded in 2008 by people engaged in network technology, the 1937CN team joined the Sino-Japanese network warfare in 2012 and the Sino-Vietnamese version in 2013, according to Liu.

"The team has engaged in cyber security technology research in recent years. Many of the members work in cyber security companies," said Liu.

Liu announced on his Sina Weibo account on Saturday that media reports blaming the team for the attacks were "irrational and unscientific."

"The 1937CN team sticks to its consistent stance, namely, no participation, no admission and no acceptation," read the announcement adding that the South China Sea belongs to China.

In an interview with Hong Kong-based newspaper Ming Pao on Sunday, Liu said that the 1937CN team had moved from hacking activities to cyber security technology in recent years for diplomatic and legal issues, Liu said.

However, according to Liu, some members of his team may still participate in cyber attacks under the name of the team, but refused to make any further comment.