Hong Kong's Chief Executive John Lee says "no activities that contravene the law should take place," when asked about whether citizens could publicly mourn the Tiananmen Square crackdown. Tuesday, June 4, marks 35 years since Beijing's deadly clampdown on pro-democracy demonstrators. Hong Kong used to be the only place under China's rule where public commemorations of the event could take place. "It is important we all bear that in mind to be on guard all the time against attempts to cause trouble to Hong Kong, particularly disturbing public peace," Lee says. IMAGES AND SOUNDBITES