1/2 Introducing of National Security law placards are placed at a secondary school, ahead of National Security Education Day, in Hong Kong, China April 12, 2021. Picture taken April 12, 2021. REUTERS/Tyrone Siu Read More Beijing's top representative in Hong Kong warned foreign powers on Thursday that they would be taught a lesson if they tried to use the global financial centre as a "pawn", as tensions escalated between China and Western governments over the city. Luo Huining, the director at China's Hong Kong Liaison Office, was speaking at a ceremony to mark an "education day" for the National Security law, which authorities have organised to promote the sweeping legislation China imposed last year.