BEIJING: Several top Chinese rights activists have disappeared into police custody as a web campaign urged angry citizens to mark the Middle East's ''Jasmine Revolution'' with protests, campaigners say.

Up to 15 leading rights lawyers and activists have disappeared since Saturday, said campaigners, while the government appeared to censor internet postings calling for the demonstrations.

In a speech on Saturday, the President, Hu Jintao, acknowledged growing social unrest and urged the ruling Communist Party to better safeguard stability while also ordering strengthened controls over ''virtual society'' or the internet.

''It is necessary to strengthen and improve a mechanism for safeguarding the rights and interests of the people,'' the Xinhua news agency quoted Mr Hu as saying.

A key to the goal was to ''solve prominent problems which might harm the harmony and stability of the society … safeguard people's rights and interests, promote social justice, and sustain sound social order,'' he said.