China’s successful test run of its first aircraft carrier—a former Soviet ship refitted with updated weaponry—evoked international concern on its maiden voyage.

Euronews reported the move is considered a step in the nation’s “long-term plan to build a carrier force of four vessels to boost its power on the Asian region’s seas which are riddled with territorial disputes.”

The ship’s “symbolic significance outweighed its practical importance,” a military expert told the news agency, adding that it is still far from being an “effective war machine” and years of pilot training will be required.

“The vessel nonetheless sends a powerful message both to China’s domestic audience, for whom a carrier has for decades been equated with national strength, and to the U.S. and its regional allies, many of whom are embroiled in territorial disputes with Beijing,” The Wall Street Journal reported.

In response, two American carriers were sent to the region. According to Voice of America, “The United States has expressed concern about Beijing’s lack of transparency regarding the carrier. But Chinese officials have responded that the vessel is not a threat to anyone and that its primary purpose is scientific research and training. They also have pointed out that China is the only one of the five permanent members of the United Nations Security Council without an operational aircraft carrier.”

Japan and Taiwan also questioned the larger nation’s motives, as reported by Agence France-Presse.

“Taiwan’s defence ministry has expressed alarm at China’s naval buildup although experts say it may still take time for the People’s Liberation Army to operate its first carrier group complete with fighter jets.”