China's elaborate efforts to smother dissenting views at this Olympics have run into one unexpected obstacle – US President George W Bush.

Mr Bush signed up early to attend the Beijing games at a time when some world leaders were flirting with boycotts or complaining that their August schedule was already full up.

Yet during his four-day trip to the Chinese capital, which finished yesterday, he has surprised even human rights groups by the directness of his comments.

In an interview with NBC yesterday, Mr Bush said that he had used his meetings with Chinese President Hu Jintao to urge more action from China to resolve the crisis in Darfur. “My attitude is that if you have relations with Mr Bashir [Sudanese president Omar Hassan al-Bashir], think about helping to solve the humanitarian crisis in Darfur,” he said. “That is my message to the Chinese government.”

In the process, Mr Bush has woven a surprisingly deft path between voicing public criticisms about issues China is deeply sensitive about and showing respect to his Chinese hosts. While so much of US foreign policy has come under heavy criticism during the current administration, Mr Bush has won plaudits for the way he has managed the ever more complicated and important relationship with China.

In the television interview yesterday, he said attending the games helped build a relationship of trust with China. “Coming here is a sign of respect for the Chinese people,” he said. “This is a big, important nation.”

His support for the games was appreciated in Beijing, especially after the March unrest in Tibet threatened to trigger a boycott by world leaders. At the opening extravaganza on Friday, he became the first US president to attend an Olympics outside the US – a substantial PR victory for China.

Mr Bush has been in his element at the sports arenas, giving a pep talk to the US men's basketball team before their clash with China and joking with the women's beach volleyball duo.