Demonstrations are planned in districts across the city on Tuesday during the lunch break, with further protests planned in the evening.
China said on Monday U.S. military ships and aircraft would not be allowed to visit Hong Kong, and also announced sanctions against several U.S. non-government organizations for encouraging protesters to "engage in extremist, violent and criminal acts".
When asked about the protests in the past weekend, Lam said it was regrettable that there had been violence again, with roadblocks and petrol bombs thrown in Kowloon.
Lam added during the press conference that, in her view, the new USA laws will affect business confidence and create instability for the more than 1,300 US companies in the city.
There have been past incidences when Beijing has denied US port calls to Hong Kong due to diplomatic disputes. It said it had suspended taking requests for US military visits indefinitely, and warned of further action to come.
The sometimes violent unrest that has rocked Hong Kong represents the biggest challenge to stability for China's ruling Communist Party since the 1989 Tiananmen Square crackdown in Beijing.
"We have a long track record of successful port visits to Hong Kong, and we expect that to continue", said a U.S. State Department official, who spoke on condition of anonymity.
Separately, the justice secretary, Teresa Cheng, said she would return to her office on Wednesday after being on sick leave for more than two weeks following an altercation in London during which she was injured.
"They shoulder some responsibility for the chaos in Hong Kong and they should be sanctioned and pay the price", said Hua.
Lam told reporters on Tuesday that she strongly objects to the legislation enacted last week and expressed regret over what she described as foreign interference.
Mr Trump had hesitated on signing the Hong Kong measure into law, fearing the effects on trade talks, but the bill enjoyed almost unanimous support in Congress which could have overriden his veto. The government has previously offered relief of about HK$21 billion (US$2.7 billion) to support the economy, particularly the transport, tourism and retail sectors.
Retailers have been especially hard-hit. Hong Kong is famously a top shopping destination for Chinese tourists.
The protesters' demands include universal suffrage, an investigation into alleged police brutality and an end to Beijing's perceived efforts to undermine democratic freedoms promised when the former British colony was handed back to China in 1997.
China denies interfering in Hong Kong's affairs and says it is committed to the "one country, two systems" framework guaranteeing the territory a high degree of autonomy.
As Beijing has not fully elaborated on the sanctions, it remains unclear how much impact the countermeasures will have on the United States.
China today indefinitely suspended US military ships and aircraft from visiting Hong Kong. Lam said that Beijing's response is a matter of diplomacy that Hong Kong will follow up in accordance with the central government's instruction.
Riot officers fired tear gas and pepper-spray balls in clashes with protesters Sunday night.