Police in London on Friday said they were investigating an assault after a Hong Kong minister fell to the ground as she was jostled by demonstrators.
Justice secretary Teresa Cheng had been due to give a lecture at the Chartered Institute of Arbitrators (CIArb) in Bloomsbury Square, central London, on Thursday evening.
But the CIArb said the event was cancelled because "whilst entering the building (Cheng) was assaulted by a crowd".
It added: "As a result she sustained an injury to her arm."