Hong Kong is part of China, so the Chinese are entitled to do that.

The concern is that the refusal is likely an expression of China’s disapproval of the US/Philippines alliance, and joint US/Philippine opposition to China’s expanionism in the South China Sea.

“Beijing denied a US aircraft carrier permission to make a port call in Hong Kong, a US consulate official says, a rejection that comes amid escalating tensions in the South China Sea.

The Chinese Foreign Ministry told the US on Thursday night the visit by the USS John C. Stennis would not be allowed, said the official, who requested anonymity.

US defence chief Ash Carter visited the Stennis earlier this month.

“[The ministry] needs to approve every ship coming into Hong Kong. [They] said ‘no’ to the carrier,” the official said, adding the reason for the denial was not clear.

In a written reply to the South China Morning Post’s inquiry, the ministry said on Friday night that port calls made by US warships and military aircraft were examined on a “case by case basis in accordance with sovereignty principles and specific circumstances”.

Carter flew to the nuclear-powered carrier for a two-hour visit on April 15, as it sailed about 100km west of the Philippine island of Luzon. Experts said the move likely irritated Beijing as Carter was accompanied by his Philippine counterpart, Voltaire Gazmin.”