Hong Kong's June 4 vigil will also support mainland Chinese arrested for supporting Occupy

The annual candlelight vigil that commemorates the Tiananmen Square crackdown will this year also pay tribute to some 300 mainlanders arrested for backing Hong Kong's Occupy movement.

They may have nothing to do with June 4, but expressing support for them would highlight the shared destiny of the democratic development of both Hong Kong and China, said Albert Ho Chun-yan, chairman of the Alliance in Support of Patriotic Democratic Movements of China, which is organising the vigil.

At the Victoria Park vigil, speakers will convey the plight of those arrested across the border. Some were arrested after posting on social media photos of themselves holding placards that read "we support the umbrella movement." Most were in Guangdong, Beijing and Shanghai.

Ho said the young activists had only done "simple, peaceful acts. They were innocent."

At least 20 of them were still being detained without legal proceedings initiated against them yet, Ho said.

He said the figures were compiled by activist groups that had been approached to help those arrested, such as Amnesty International and China Human Rights Lawyers Concern Group, which Ho co-founded.