China showed off an elite helicopter unit to foreign media on Tuesday in its latest bid to address concerns about its growing military might amid increasingly aggressive moves to assert its sovereignty over the South China Sea.

China organises annual tours of military bases to try to assuage those concerns and to answer criticism over a perceived lack of transparency, but officials refused to answer any contentious questions.

While the Defence Ministry announced over the weekend it would set up a formal military garrison for the South China Sea, officers accompanying reporters to the Tongzhou base in Beijing’s far east avoided the issue.

“Our military’s aim is to protect peace. The training exercises we carry out are normal and in line with what we always do,” Zhang Zhilin, the jocular commander of the Army Aviation 4th Helicopter Regiment, told reporters.

China has conflicting claims with the Philippines, Vietnam, Brunei, Malaysia and Taiwan across the South China Sea, key shipping lanes thought to contain rich energy reserves.

Asked about whether he and his comrades could or would deploy to the South China Sea, Zhang answered simply: “Our deployments are decided by the higher ups.”

His unit, which operates Harbin Z-9 attack helicopters, a licensed-built version of the Eurocopter Dauphin II, as well as older Russian Mil Mi-17 transport helicopters, also flies China’s astronauts back to base when they return to Earth.

China’s helicopter programme made headlines last month when United Technologies Corp said it had sold China software that helped Beijing develop its first modern military attack helicopter, the Z-10.

Western experts say the Z-10, first delivered to China’s People’s Liberation Army in 2009, is developing into one of the world’s most modern and capable combat helicopters.