Humanitarian China said the event they held on May 31 was hosted by a paid account and was attended by over 250 people worldwide via video-conferencing platform Zoom, while more than 4,000 streamed it on social media, many of whom were from China. The account was shut on June 7, it said in a statement. Zoom confirmed the US-based account had been suspended but had now been reactivated.

“When a meeting is held across different countries, the participants within those countries are required to comply with their respective local laws. We aim to limit the actions we take to those necessary to comply with local law and continuously review and improve our process on these matters.”

Humanitarian China founder Zhou Fengsuo said on his Twitter account that the group had yet to receive an answer from Zoom about why its account was closed.

The group said in a statement that Zoom was essential for reaching Chinese audiences “remembering and commemorating Tiananmen Massacre during the coronavirus pandemic”.

California-based Zoom has said it is working to fix flaws in the security of its platform as user numbers soar with the imposition of lockdowns and social distancing restrictions around the world.

Last month, Zoom said it was suspending free user registrations in China, which analysts said was targeted at reducing the company’s exposure to China.