Beijing's top representative in Hong Kong warned foreign powers on Thursday not to use the city as a pawn.
Luo Huining made the comments at a ceremony to mark an "education day" for the National Security law.
Authorities organized the event, attended by Hong Kong's chief executive Carrie Lam, to promote the sweeping new legislation China imposed last year.
"Hong Kong citizens also have the shared obligation to safeguard national security, sovereignty, to unite and uphold our territorial integrity, just like Chinese citizens across our entire country."
In February, Hong Kong unveiled national security education guidelines.
They include teaching students as young as six about colluding with foreign forces, terrorism, secession and subversion -
the four main crimes in the new law.
The law has drawn sharp criticism from the West for curbing rights and freedoms in the former British colony.
In the background of the event, a small protest was staged near the venue of the ceremony...
four activists marched shouting slogans calling the law a "weapon of mass destruction".
Meanwhile, supporters of the law say it has restored order following mass anti-government and anti-China protests in 2019.