US ambassador Jon Huntsman on Wednesday defended detained Chinese artist Ai Weiwei for challenging Beijing to better serve the people, in his final public speech before a possible presidential bid.
Huntsman also urged the Chinese government not to use the Internet to create distrust and warned misperceptions in the United States and China threaten to lead to policies that could undermine their relationship.
US Secretary of Commerce Gary Locke has been nominated to replace Huntsman, who is due to leave Beijing later this month as he flirts with seeking the Republican nomination to challenge Barack Obama for the presidency next year.
Huntsman said future ambassadors would press Beijing on human rights, citing jailed Noble Peace Laureate Liu Xiaobo, blind Chinese activist Chen Guangcheng and Ai -- the latest to be rounded up in a crackdown on dissent.
"They will continue to speak up in defence of social activists, like Liu Xiaobo, Chen Guangcheng and now Ai Weiwei, who challenge the Chinese government to serve the public in all cases and at all times," he said.
The 53-year-old artist -- known as much for his art as for activist work that frequently takes aim at the ruling Communist Party -- has not been heard from since Sunday, when he was detained at Beijing's airport while trying to board a flight to Hong Kong.
Huntsman was in Shanghai to give a speech on US-China relations and made no mention of his future plans at the event.
The former Republican governor of Utah and one-time deputy US trade representative who took up his post in China in August 2009, has said he will step down as of April 30.
He stirred speculation about a possible bid for the Republican presidential nomination in 2012 with a Newsweek interview late last year in which he suggested he had one political run left in him.
Huntsman suggested China should open up its Internet, which is fenced in by an ever-expanding system of control and censorship dubbed the "Great Firewall of China", aimed at snuffing out information the government deems a threat.
"Use the tools we have available to us, including, especially, the Internet. But use them to share information, increase understanding and build relationships, not to erect barriers or foment distrust," he said.