Another scholar, Xu Zidong, from Hong Kong's Lingnan University, believes the decade-old hunt for the terrorist mastermind distracted the US from engaging China on a number of contentious issues.

"Before the 911 attack, the US saw China as its biggest threat. Relations between the two countries were very tense after George W. Bush took the office in January 2001," Xu said.

In February that year, the US Secretary of Defense, Donald Rumsfeld, upped the pressure on China by ordering a re-evaluation of Sino-US military communications strategy. A month later, Bush ordered all departments to re-evaluate their China strategy.

Two months later a US navy aircraft collided with a Chinese military fighter jet near Hainan Island, killing the Chinese pilot Wang Wei. The US aircraft made an emergency landing on Hainan and its crew of 24 were detained until the US delivered a written account of the incident to the Chinese government.

Three weeks after the military jet incident, Bush announced a $4.5-billion weapons sale to Taiwan, the largest since the president's father sold 150 F-16 fighter jets to the island almost decade earlier.

President Bush added fuel to the fire and caused an uproar in China when he told American reporters that the US would take all necessary means to protect Taiwan.

"The Taiwan question has always been the most contentious issue between the US and China and Bush's remarks were intolerable. To be honest, we believed the situation was going to continue to escalate," said Zhu Feng, professor of International Relations at Peking University.

In September of that year, New York's World Trade Center buildings were attacked and US attention become firmly fixed on to the Middle East.

"After 911, I had a sense of relief that the pressure between China and the US would ease off, but the discontent and anger among Chinese isn't easily forgotten," Xu said.

Over the past decade, China and the US have cooperated on a number of fronts to combat terrorism. Two weeks after 911 officials from both countries met in Washington to develop an anti-terrorism framework.