US politicians from both parties have expressed support for protesters in Hong Kong as footage showed convoys of Chinese military vehicles arriving in Shenzhen, near the border of the semi-autonomous territory.
The vehicles were pictured on Tuesday 28 kilometres away from Hong Kong, where protesters have shut the airport for a second day.
Footage on social networks showed large numbers of camouflaged trucks and armoured personnel carriers assembling in the city.
The vehicles belong to the Chinese People’s Armed Police, a paramilitary force with close links to the People’s Liberation Army, local news networks said.
In one clip on Twitter, a column of military vehicles enter the Shenzen Bay Sports Centre.
US President Donald Trump urged caution on Tuesday, saying US intelligence informed him of the military build-up.
“Everyone should be calm and safe,” Mr Trump tweeted.
The Trump administration on Monday said the dispute was an issue strictly "between Hong Kong and China".
“The Hong Kong thing is a very tough situation," Mr Trump said. "I hope it works out peacefully.
"I hope nobody gets hurt. I hope nobody gets killed. I hope it works out for everybody, including China.”
“The People's Police Army is legitimately responsible for handling riots, serious violent crimes, terrorist attacks and other incidents that threaten social security.” -caption on video posted by @PDChina showing armed police gathering at #China border Shenzhen near #HongKong pic.twitter.com/FbEfeeDG2B
— Eunice Yoon (@onlyyoontv) August 12, 2019
Paramilitary forces are believed to have been gathering in Shenzhen since Saturday.
Chinese state media has described the build-up as preparation for “large-scale exercises".
Chinese riot police earlier conducted a drill with thousands of participants, in what was considered to be a warning from Beijing about its ability to end two months of protests in the global financial centre.
The UN has voiced its concern at the “escalation of violence".
Rupert Colville, spokesman for the UN High Commissioner for Human Rights, urged the authorities to act with restraint and “to ensure that the right of those who are expressing their views peacefully are respected and protected".
Chris Patten, the last British governor of Hong Kong before it was handed back to the Chinese in 1997, told BBC Radio that Chinese military intervention in the city would be a catastrophe.
In the US, Republican Senate majority leader Mitch McConnell and Democrat Speaker of the House Nancy Pelosi backed the protesters.
"The people of Hong Kong deserve the true autonomy that was promised, with the full rights guaranteed by the Hong Kong Basic Law and international agreements,” Ms Pelosi said.
The people of Hong Kong are trying to preserve the promise of One Country - Two Systems. If we don’t speak out for human rights in China because of commercial interests, we lose all moral authority to speak out elsewhere.
— Nancy Pelosi (@SpeakerPelosi) August 13, 2019
Mr McConnell said that any crackdown by China would not be acceptable:
The people of Hong Kong are bravely standing up to the Chinese Communist Party as Beijing tries to encroach on their autonomy and freedom. Any violent crackdown would be completely unacceptable. As I have said on the Senate floor: The world is watching. https://t.co/5VPm5P4PfB
— Leader McConnell (@LeaderMcConnell) August 12, 2019
Senator Elizabeth Warren, who is running for presidential candidate in the Democratic primaries, also issued a statement announcing solidarity with the protesters:
The people of Hong Kong are making clear that they will not tolerate repression, and their movement affirms: The power is with the people. They deserve our support and the support of the world. https://t.co/Ap0OQSsN0N
— Elizabeth Warren (@ewarren) August 12, 2019
The recent statements from Democrats and Republicans show the continued importance of the issue in the US.
Last June, more than a dozen senators from both parties issued a statement supporting the protests.
