China's defense ministry said Wednesday that an aircraft carrier being readied for sea trials will be used for scientific research, experiments and training.

Ministry spokesman Geng Yanshen told reporters Wednesday that despite its carrier program, China remains committed to a naval strategy of defending its own shores. The nearing completion of the carrier has worried some of China's neighbors, who fear it could be deployed as part of a battle group to project Chinese power in disputed areas including the South China Sea.

Geng's comments marked the ministry's first official comment on the carrier, although senior military officials have discussed it and photos have appeared in Chinese media. There had been speculation that sea trials would begin July 1 as China marked the 90th anniversary of the founding of its ruling Communist Party.

Geng said only that the timing of the maiden voyage will depend on the schedule of the refit.

The vessel is being rebuilt from the stripped-down hull of the carrier Varyag, which was purchased from Ukraine and towed to a shipyard in the northern Chinese port of Dalian in 1998. China is expected to use knowledge gained from the process to build at least three more carriers.

Geng said the process of training pilots how to fly planes off an aircraft carrier is also “in progress.”