Chinese officials at the embassy in London have shoved two women as they attempted to lay flowers to mark the 25th anniversary of the Tiananmen Square crackdown.
Kate Allen, director of Amnesty International UK and Wang Ti-Anna, daughter of an imprisoned Chinese dissident whose story was recently told by IBTimes UK, were attacked by two members of the embassy as they were placing flowers on the steps.
They pushed the two women and threw the bouquet after them. A police officer told the two officials to return to the embassy. Kate Allen and Wang Ti-Anna have decided to file a lawsuit for common assault.
"If this is the sort of brazen aggression that Chinese officials feel confident they can get away with in London, it is frightening to think what is happening in China," Allen said.
"This was a peaceful attempt to commemorate the Tiananmen protests and remember all those who lost their lives in the bloody crackdown. The violence it was met with shows the true colours of the Chinese authorities."
The other activist told the BBC that she was "really shocked" and felt "upset by their violence to what seemed like a peaceful act of commemoration".
Twenty-five years after the military crackdown on the pro-democracy protests, China is seeking to curb all discussion of the massacre. The anniversary has been preceded by scores of detentions and several people have been place under house arrest.
The government has also imposed its widest block on Google services in the country yet, erecting what has become known as the Great Firewall of China.