At least 22 people were injured when the violent clashes broke out in Hong Kong's northern town of Sha Tin on Sunday night, reports the South China Morning Post.
Commissioner of Police Stephen Lo Wai-chung described protesters involved in pitched battles at shopping centres as "thugs", and vowed to track down those responsible and hold them accountable.
Lam made the remarks after visiting injured police officers at a hospital in Tai Po on Monday morning alongside Secretary for Security John Lee Ka-chiu.
She said police officers had remained restrained while "thugs attacked them". She also urged people to defend the rule of law.
"The rule of law has been the cornerstone of Hong Kong's success... and to defend it, both the Hong Kong people and the government need to obey the law," she said.
She also dismissed claims of her resignation after the Financial Times cited two people on Sunday saying that Lam had volunteered to step down on several occasions in recent weeks over mass protests in the city but Beijing had refused.
Lam added that while she was currently facing much difficulty, she was still committed to her work for the remainder of her term, which ends in June 2022.
( With inputs from IANS )