GENEVA (AFP) - China defended its human rights record to the UN on Tuesday, insisting it has undertaken sweeping reforms as Tibetan activists said more must be done to hold Beijing to account.

China's special envoy Wu Hailong told the UN Human Rights Council that his country had lived up to a pledge made in 2009 when China was last under scrutiny by the watchdog.

"The Chinese government made a solemn commitment when China undergoes the next review, the world will see a China with a more prosperous economy, improved democracy and the rule of law, a more harmonious society and people living in greater happiness," Mr Wu said.

In 2009, the council had urged China to make more efforts in areas including poverty reduction, judicial reforms and ethnic minority rights.

"Four years have passed, and I want to tell you that the above recommendations either have been implemented or are being carried out, and our commitment has been basically fulfilled," Mr Wu said.

All 193 UN member states are meant to undergo reviews of their rights record every four years.

In the run-up to Tuesday's review, human rights campaigners raised the alarm about the disappearance of Chinese activist Cao Shunli, who had been due to attend the session.

In a statement on Monday, the European Union's top diplomat Catherine Ashton had urged Beijing to clarify what had happened to Mr Cao, and to do nothing to hamper the participation of campaigners at the UN Human Rights Council.

Human Rights Watch, meanwhile, said China must demonstrate its commitment by ending a crackdown on human rights activists, including harassment, arbitrary arrest and torture, as well as stop muzzling the media and halt abuses against its Tibetan and Uighur minorities.

'We expect China to lie' About 120 people have set themselves on fire in Tibet and neighbouring areas since 2009, most of them dying, in a grisly series of protests against Chinese rule.

"China is good about signing human rights treaties but terrible about putting them into practice," said Sophie Richardson, China director at Human Rights Watch.

"The Human Rights Council review provides UN members the occasion to look at whether those commitments are being implemented - or instead violated." At the review, diplomats from dozens of countries quizzed Mr Wu and members of his delegation about the steps Beijing had taken.

While acknowledging China's efforts, Western delegations in particular urged Beijing to further reduce the number of crimes that carry the death penalty and at least to introduce a moratorium on capital punishment.

They also urged China to sign an international accord on civil and political rights and, in the meantime, to protect basic freedoms of assembly and opinion, as well as to allow UN human rights monitors to visit Tibetan and Uighur areas.

Before Tuesday's session, Tibetan activists hammered their message home.

At dawn, four protesters from the groups "Students for a Free Tibet" and the "Tibetan Youth Association in Europe" climbed scaffolding on the UN building in Geneva, currently under renovation, before jumping down to the middle of the facade using climbing ropes.

They unfurled a massive banner reading: "China Fails Human Rights, UN stand up for Tibet," and shouted: "Free Tibet!"

UN security acted swiftly to cut down the banner and arrest the protesters, but also to grab journalists' press accreditation and usher them away from the scene.

"The protest went really great," said Pema Yoko, deputy director of Students for a Free Tibet.

It was important to draw attention to Tibet's plight, she insisted, stressing that "we expect China to blatantly lie about their rights record in Tibet".