Fears mounted Wednesday that the ongoing protests in Hong Kong could spark a repeat of the 1989 Tiananmen Square massacre, as Chinese authorities increased their military presence not far from the border of the semi-autonomous territory that has been the scene of a growing pro-democracy movement throughout this summer.

While Hong Kong’s heavily trafficked international airport reopened Wednesday for the first time in three days, residents remained on high alert after two days of protests had been marred by violent clashes with police and China’s leaders darkly warned that “terrorists” were behind the unrest.

Satellite imagery appeared to show Chinese military vehicles gathered inside a sporting arena in the city of Shenzhen across the border from Hong Kong. Local media reported heightened numbers of uniformed officers with the People’s Armed Police Force outfitted with riot gear.

In one incident Wednesday, Hong Kong police fired tear gas at a group of pro-democracy protesters rallying outside a police station in a crowded urban neighborhood. Police also announced they arrested five people over violence in the airport protests, the Associated Press reported.

While Beijing’s Communist Party leadership is clearly frustrated at its inability to contain the protests, analysts say that the probability of a Chinese military intervention remains relatively low.

Chinese President Xi Jinping “is a tough guy. He’s a high-stakes gambler,” said Jerome Cohen, an adjunct senior fellow for Asia Studies at the Council on Foreign Relations.

“He knows the dangers of course, of repeating that June 4th, 1989 Tianamen-type massacre. He doesn’t want to do that. It would be a disaster for him personally, his leadership, his people, and certainly for Hong Kong and international security,” he said on a Wednesday afternoon call with reporters.

Chinese officials have described the movement of paramilitary forces closer to Hong Kong as “training exercises,” but have also harshly criticized comments from the U.S. and from world leaders in support of the protesters.

In the wake of the protests, the State Department issued a travel advisory for Hong Kong due to “civil unrest.”

The department cited “political demonstrations” that have at times involved tear gas and “spilled over into neighborhoods other than those where the police have permitted marches or rallies.”

“These demonstrations, which can take place with little or no notice, are likely to continue,” the department added.

In Hong Kong, scores of demonstrators took to social media to apologize for the “inconvenience” caused by the protests, including the closure of the airport.

“We would like to sincerely apologize for all inconvenience caused by the peaceful demonstration at the HK International Airport,” tweeted activist Joshua Wong.

Mr. Cohen explained that the dispute, which has spread far beyond the original opposition to a proposed new extradition law with the mainland, will likely see more clashes between the protesters’ tech-savvy flash mobs and an increasingly aggressive Hong Kong police agency.

“Violence is inevitable,” Mr. Cohen said. “You’ve got lots of people in the street and police try to restrain them. That leads inevitably to violence.”

Officials in Hong Kong appeared to be sharpening their rhetoric against the protesters.

In a statement Wednesday, a spokeswoman for the State Council’s Hong Kong and Macao Affairs Office, Xu Luying, said “radical violators have completely breached the bottom line of law, morality and humanity.”

“Their flagrant acts of serious violent crimes in public are shocking and chilling,” she said and claimed the clashes “seriously damaged Hong Kong’s international image and hurt the feelings of compatriots on the mainland.”

Mr. Cohen said the stakes are rising for both sides as the protests continue.

“Hong Kong is the leading symbol of the Communist Party’s vindication of China’s rise and China’s reintegration of the country, completing the reunification of the mainland against the long depredations of Western colonialism and Japanese colonialism,” said Mr. Cohen.

China, he added, has “got to be careful because if they reassert real control through the use of force, that’s a terrible result.”

• This article was based in part on wire service reports.

Sign up for Daily Newsletters Manage Newsletters

Copyright © 2020 The Washington Times, LLC. Click here for reprint permission.