With trade issues likely to dominate this week's summit between President Hu Jintao and US President George W. Bush, rights activists are calling for the human rights dialogue between the two countries to resume as soon as possible. Their comments came as New York Times researcher Zhao Yan remained in detention in Beijing more than three weeks after his charges for leaking state secrets and financial fraud were dropped. Mo Shaoping, Zhao's lawyer, said he filed a letter to the Supreme People's Procuratorate late last month demanding his immediate release as he was being held illegally. 'But there hasn't been any response yet,' he said. John Kamm, executive director of the San Francisco-based human rights organisation, the Dui Hua Foundation, said Zhao topped his group's list of human rights concerns. 'All of us who believe in the rule of law in China are just astonished by what has happened in Zhao's case. How can someone who has had an indictment withdrawn still not be freed?' he asked. Zhao was arrested in September 2004 and had faced 10 years in jail after the state security apparatus charged him with telling The New York Times details of rivalry between President Hu and his predecessor, Jiang Zemin . The government often releases dissidents ahead of leaders' foreign visits or when international figures visit China as a gesture of goodwill. Meanwhile, the trial in Guizhou of another journalist, Li Yuanlong, had been postponed, his lawyer Li Jianqiang said. The lawyer based in Shandong said a trial had been scheduled for early this month, but he was later told - by another lawyer, not the court - that another date would be fixed at the end of the month. Li, 45, was charged with 'incitement to subvert state power' on February 9, five months after he was detained for posting politically sensitive essays on the internet using a Hotmail account. For Mr Kamm, however, the key issue is whether China and the US will resume their official human rights dialogue during Mr Hu's visit. 'The big question is not whether someone will be released or not before Hu Jintao goes to the US, the big question is will the US and China find the way to constructively engage in the question of human rights,' he said. Mr Kamm said talks could resolve some of the cases, but a lack of dialogue would hamper the ability to solve all cases. Although it has been reported that Beijing and Washington will finalise an agreement to resume human rights dialogue during the summit on April 20, Mr Kamm said uncertainty remained. 'The two sides are discussing [resuming the dialogue] very sincerely and very aggressively. We are right in the middle of a poker game, and you want me to tell you who will be the winner of the game, I don't know - it's 50/50.' The dialogue mechanism was set up in the 1990s by the Clinton administration. It was suspended in March 2004 after the US urged a UN human rights watchdog to condemn what it called the mainland's backsliding on rights. The jailing of mainland journalists and tightening of censorship have caught international attention. Michael Davis, a law professor from Chinese University, said Beijing's suppression of the media had been prominent in the view of the international human rights community. 'What has happened in the past couple years is that the current Chinese government appears to be targeting reporters and internet users as it endeavours to keep the lid on its control of information in China,' he said. 'As the Sino-US relationship has become testier over trade, and occasionally security disputes, the US may feel more comfortable taking the gloves off,' Mr Davis said.