Obama on Friday ordered Ralls Corp, owned by two Sany executives, to remove all property and installations from its sites within two weeks and divest all of its interests in the wind-farm project within 90 days. It is the first time in 22 years a US president has blocked a transaction as a national security risk.

The navy conducts training for bombing, electronic combat manoeuvres and develops drones in the area around the site, the base's website says.

Sany owns China's biggest machinery maker. Duan Dawei, Sany's chief financial officer, and Wu Jialiang, a vice-president of the group and general manager of Sany Electric, a group unit, own Ralls, according to court filings. Sany, based in Changsha, Hunan, is run by billionaire Liang Wengen.

Ralls wanted to place Sany-made wind turbines at the Oregon installations after buying land and other rights this year. The project sites are near or within the restricted navy airspace, the Treasury Department says.

Zhou said other wind farms with foreign investment had been built near naval facilities in Oregon without being called a threat to national security.

The block replaces an interim order in July by the government's Committee on Foreign Investment in the US.