A Hong Kong man died after stabbing a police officer and then himself in a case the city’s security chief described as “a lone wolf terrorist attack”, as China’s Communist party marked the centenary of its founding.

The attack late on Thursday evening, which left the officer in a serious condition, occurred despite an overwhelming security operation in the Asian financial centre to prevent any protests.

“I strongly condemn this kind of violence,” said Hong Kong chief executive Carrie Lam. “These behaviours are clearly directed at the stability of our society.”

The attack came despite the government’s success in extinguishing Hong Kong’s anti-government protest movement through mass arrests of activists and the introduction of a national security law last year.

Analysts said the incident would be used to justify a further crackdown as Beijing seeks to bring the city to heel after mass demonstrations in 2019 to protect freedoms guaranteed to the city after its 1997 handover to China.

The 28-year-old officer was stabbed outside a department store in Causeway Bay, one of the busiest shopping districts in the city and the usual gathering point for protests.

The 50-year-old suspect then stabbed himself in the chest with the same weapon and was certified dead after being sent to hospital. Videos showed him lying in a pool of blood at the scene.

Hong Kong’s secretary for security Chris Tang, without specifying, vowed to target those who “advocated violence, incited hostility, hatred towards society and country”, which he said were the primary factors behind the incident.

“These people pushing from behind have their hands full with blood,” he said.

Experts said even though the man’s motivation was not clear, the case would be seen by authorities as evidence they had not done enough to quell Hong Kong’s anti-government movement.

“It was such an important day for the regime, [yet] with so many measures there are still problems,” said Ray Yep, a political scientist at City University of Hong Kong.

Others said pro-Beijing politicians in the city would seek to equate the stabbing with the wider pro-democracy movement. “This may be used as an argument for the tight controls under the national security law, or perhaps even an expansion of its application,” said Ian Chong, a professor of political science at the National University of Singapore.

A handful of people went to the scene of the stabbing with white flowers on Friday to mourn the death of the attacker.

Separately, police found flammable objects that were thrown at Government House, Lam’s residence, and arrested at least 19 people for acts including distributing seditious publications and possession of weapons.

The incidents came after Chinese President Xi Jinping presided over a mass ceremony in Beijing’s Tiananmen Square to mark the party’s founding in 1921.

Thursday also marked the 24th anniversary of Hong Kong’s 1997 handover from the UK to China.