The Chinese People’s Liberation Army (PLA) used social media on Wednesday to publish a short video clip of Hong Kong air defense drills.

A military analyst told the island’s leading dissident newspaper, Apple Daily, that the incongruous 48-second video was meant as a warning to the United States against interfering with China’s oppression of Hong Kong.

The analyst, Anthony Wong of the International Military Association in Macau, noted that the video was labeled with Hong Kong’s name in English instead of Mandarin, a sign that its intended audience was the United States, along with Beijing loyalists in Hong Kong who want to see the PLA sending belligerent messages to the U.S.

“There’s no question about it, it’s to show the U.S. and to show the ‘blue ribbons’ in Hong Kong,” said Wong. 

Hong Kong demonstrators have a habit of wearing colored ribbons to identify with causes and political factions. Pro-democracy protesters wore yellow ribbons during the 2014 Umbrella Movement demonstrations, while supporters of the Hong Kong government and its masters in Beijing wore blue.

Wong said the PLA wanted to send a message to the U.S. that “if you come near Hong Kong, we won’t hold back.” He referenced reports that American planes have been seen flying off the coast of southeastern China several times in the past few weeks. 

Those planes were most likely reconnaissance aircraft connected with U.S. freedom of navigation operations in the South China Sea, but evidently the PLA thinks — or wishes to give the impression it thinks — the American military is planning to intervene in Hong Kong.

The PLA has been increasing the tempo of military drills across East Asia as relations with the U.S. deteriorate, with noteworthy surges after two American aircraft carriers held an unusual exercise in the South China Sea in July and Health and Human Services Secretary Alex Azar visited Taiwan this week.

When Azar made his visit to Taiwan, Chinese state media angrily threatened to retaliate by holding live-fire missile drills near Taiwan and Guam, where the U.S. has a major airbase. The editorial that made this threat was re-posted on the PLA’s English-language news website.