Sansha, China's southernmost prefecture-level city, was finally established on Tuesday, as the nation strengthens its sovereignty claims over the South China Sea amid frayed relations with neighboring countries.

A ceremony was held on Tuesday to mark the establishment of the new city on Yongxing Island, unveiling the plaques of the local Communist Party of China (CPC) committee, legislative body, administrative body as well as a local military garrison.

The ceremony came on the heels of the first session of the first Sansha People's Congress, the city's legislative body on Monday, which elected the new city's leadership.

"It was a wise decision made by the CPC Central Committee and the State Council to establish the city of Sansha to safeguard State sovereignty and security, and strengthen the protection and development of resources in the South China Sea," Xiao Jie, secretary of the Sansha City Committee of the CPC and mayor of the newly established city, said at the ceremony as quoted by CCTV.

Xiao was head of the Hainan provincial government's agriculture department before taking over the new post.

The new city government will also be devoted to developing the local economy and improving people's livelihoods, Xiao said.  

The establishment of Sansha city that administers the Xisha, Zhongsha and Nansha islands and their surrounding waters in the South China Sea, covering the nation's largest water areas of more than 2 million square kilometers, came only one month after the State Council announced the formation of the new city in the wake of Vietnam's decision to pass a national maritime law that included the Xisha and Nansha islands within its sovereignty and jurisdiction.

"Sansha city is unique within the nation's administrative boundaries, as its establishment serves to assert China's maritime sovereignty over the South China Sea amid continued territory spats with countries such as the Philippines and Vietnam," Zhuang Guotu, dean of the School for Southeast Asian Studies at Xiamen University, told the Global Times.

The military background of some of Sansha's leaders also strengthens belief in the new city's function as a sovereignty defender. Fu Zhuang, deputy director of the Hainan Provincial Civil Air Defense Office, was elected on Monday to become the first head of the city's legislative body.

However, the administrative management and economic development would still top the new city government's agenda, said Ji Qiufeng, a professor at the School of International Relations at Nanjing University.

"The new city government will play a vital role in organizing local economic development by exploring the abundant resources of the vast water areas under its jurisdiction," Zhuang said, adding that boosting the local economy also helps assert the nation's maritime sovereignty.