China's ruling Communist Party vowed a new crackdown on demonstrations against the government's tough anti-COVID-19 restrictions even as police clashed with protesters in the southern city of Guangzhou in the latest of a string of confrontations throughout the country.

Late Tuesday, China said it would 'resolutely crack down on infiltration and sabotage activities by hostile forces.' The statement from the Central Political and Legal Affairs Commission did not directly address the protests that have erupted in at least 15 cities, including the capital, Beijing, and the major financial center, Shanghai, but made clear the government's intent to enforce its rule.

In Guangzhou, a manufacturing hub home to many migrant factory workers, videos posted on social media showed security personnel wearing hazmat suits and carrying shields as they patrolled the streets.

In Beijing on Wednesday, hundreds of SUVs, vans and armored vehicles with flashing lights were parked along city streets. Police and paramilitary forces conducted random ID checks and searched people's mobile phones for photos, banned apps or other potential evidence that they had taken part in a string of demonstrations that have erupted in recent days against the government's 'zero-COVID' restrictions.

Videos have shown police arresting numerous protesters in major cities. Some of them have appeared to be protesting silently, often holding aloft a blank sheet of white paper as a statement against the country's lack of free speech, while others have taunted authorities. The numbers detained - or their fates - are not known.

Shanghai residents confront coronavirus disease (COVID-19) staff dressed in protective clothing in Shanghai, China, in this still image obtained from a social media video released Nov. 30, 2022. Video obtained by Reuters.

Some protesters have called for the resignation of President Xi Jinping, who in October was elected to a third five-year term as Communist Party leader. His government has contended that the anti-virus restrictions, which have included shutting down entire cities and regions, have saved lives.

But many Chinese have become angered at the impact of the anti-virus rules on their lives. Footage of the protests has been widely shown on social media before being scrubbed by government censors, while the strictly controlled state media has largely ignored the demonstrations.

The national news Wednesday evening was instead dominated by the death of former president and Communist Party leader Jiang Zemin at the age of 96. He was installed as the country's leader just ahead of the bloody suppression of the 1989 student-led pro-democracy movement centered on Beijing's Tiananmen Square and later presided over an era of rapid Chinese economic growth during the 1990s and early 2000s even as the Communist Party maintained rigid control of the country.

Jiang Zemin, Who Guided China's Economic Rise, Dies

The Central Political and Legal Affairs Commission statement said China 'must resolutely crack down on infiltration and sabotage activities by hostile forces in accordance with the law, resolutely crack down on illegal and criminal acts that disrupt social order and effectively maintain overall social stability.'

Xi and the party have yet to directly comment on the protests and the disruption to everyday life that the anti-pandemic rules have caused. The demonstrations have spread to college campuses and the semi-autonomous southern city of Hong Kong and have sparked sympathy protests abroad.

The government has blamed the unrest on unidentified 'hostile outside foreign forces.' As the protests continued in recent days, several Chinese cities have eased some restrictions.

The zero-COVID-19 rules have helped keep case numbers lower than in the United States and other major countries, but world health and economic leaders say the policies are unsustainable and have urged China to adopt a more targeted approach to control the pandemic. China has dismissed the advice as irresponsible.

On Wednesday, U.S. Ambassador to China Nicholas Burns said the restrictions were playing havoc with American operations in the country. In an online discussion with the Chicago Council on Global Affairs, he said 'COVID is really dominating every aspect of life' in China.

He said the restrictions are making it impossible for U.S. diplomats to meet with American prisoners being held in China, as is mandated by an international treaty, and that because of a lack of commercial airline routes into the country, the U.S. embassy has had to use monthly charter flights to move its personnel in and out.

Burns said the U.S. believes 'the Chinese people have a right to protest peacefully. They have a right to make their views known. They have a right to be heard. That's a fundamental right around the world. It should be. And that right should not be hindered with, and it shouldn't be interfered with.'

But when asked about foreign expressions of support for the protesters, Chinese Foreign Ministry spokesperson Zhao Lijian said other nations should mind their own business.

'We hope they will first heed their own peoples' voices and interests instead of pointing fingers at others,' Zhao told reporters at a daily briefing.

Some material from this report came from The Associated Press.