China's defence ministry on Thursday urged the Asia-Pacific to be on high alert as the United States steps up forward military deployment in the region, after reports of a U.S. plan to revive a Pacific airfield that launched atomic bombings of Japan.

The Chinese military is paying close attention to moves by the United States, and will firmly safeguard China's maritime rights, security and sovereignty in the region, Wu Qian, a spokesperson at the defence ministry, told a regular news conference.

Earlier in December, a U.S. air force general told Japan's Nikkei newspaper that the U.S. military will make "significant progress" towards reclaiming the Tinian North airfield from overgrown jungle vegetation in the coming months, as part of a plan to disperse aircraft across the Indo-Pacific region as China's missile threat grows.

The airfield, abandoned after World War II, lies on Tinian island, part of the Northern Mariana Islands, a U.S. territory, and about 200 kilometres (124 miles) north of Guam. (Reporting by Laurie Chen and Ryan Woo. Editing by Jane Merriman)