In a strongly worded three-minute video, Mrs Lam said: "This is not an act that shows love for Hong Kong."
"Some people resorted to dangerous, or even potentially fatal, acts," she said, adding that these actions have undermined the safety of many - including ordinary citizens, young people who had wanted to express their views in a peaceful manner, police and civil servants.
She noted that while there are different views on the extradition Bill, issues involving China and Hong Kong have been used by some people to cause conflict.
Radical confrontation is not the solution, she said.
Rioting is punishable with a 10-year jail term.
In a tearful television interview earlier on Wednesday, Mrs Lam compared young protesters to a child who is given too much leniency by his mother and then indulges in headstrong behavior.
"He will feel regret: 'Why was my mother not tough with me?'" she said, criticising herself for being too tolerant with the protesters.
Mrs Lam appeared to grow emotional when asked to respond to claims that she had "sold out" Hong Kong.
"I was born here, raised here like every other Hong Konger. For my love of this place, I have made no small amount of sacrifices," she said.
At least 72 people were injured during clashes between police and protesters on Wednesday over the contentious extradition Bill.
Among those injured were two men, who were in serious condition, said a government spokesman.
By night time, police officers were still in a stand-off with protesters on Queensway, not far from Admiralty station, even though most of the protesters had dispersed following the use of tear gas and rubber bullets.
At around 11pm on Wednesday, protesters were spotted gathering at the junction outside AIA tower in Central and the junction of Hennessy Road and Queen's Road East towards Wan Chai.
Earlier, police fired rubber bullets at protesters after they declared a "riot" as - for the second time in days - clashes broke out between police and protesters demonstrating against the Bill.
"We had no choice but to use weapons to stop these protesters from barging at our defence lines," Police Commissioner Stephen Lo Wai Chung said, speaking in Cantonese.
The top police official, however, brushed aside suggestions that a curfew would be imposed, local radio station RTHK reported.
In Beijing, Foreign Ministry spokesman Geng Shuang told reporters that China "will continue to support" Hong Kong's government. China has repeatedly said it backs the Hong Kong government amid the stand-off.
"Any actions that harm Hong Kong's prosperity and stability are opposed by mainstream public opinion in Hong Kong," Mr Geng said at a regular briefing.
Asked about rumours that more Chinese security forces were going to be sent to Hong Kong, Mr Geng dismissed it as "fake news".
20 COUNTRIES THAT HAVE EXTRADITION TREATIES WITH HONG KONG
• Czech Republic
• The Netherlands
• New Zealand
• The Philippines
• South Africa
• South Korea
• Sri Lanka
• United Kingdom
• United States of America
Source: Hong Kong Department of Justice