Uzbek President Islam Karimov has begun an official visit to China, his first foreign trip since a bloody crackdown on protesters at home.
Mr Karimov will hold talks with China's President Hu Jintao
China is one of the few countries to have backed Mr Karimov's handling of protests in eastern Andijan on 13 May.
Uzbek officials say 170 people they called Islamic extremists died, but witnesses say at least 500 were killed.
China on Wednesday reiterated its own crackdown on alleged Muslim militants, in the far west province of Xinjiang.
"Over a long period of time... forces have sought to carry out separatist and harmful activities in Xinjiang that are aimed at splitting Xinjiang from China's big family of nationalities," said the state-run Xinjiang Daily.
"We must continue to maintain our 'strike hard, high pressure' posture in the anti-separatism struggle and maintain the policy of initiating the attack and striking whenever and wherever they appear," it said.
Mr Karimov has turned down calls for an international inquiry into reports that troops shot at unarmed civilians.
Most populous central Asian former Soviet republic, home to 26m people
Ruled since 1991 independence by autocrat Islam Karimov
Accused by human rights groups of serious abuses, including torture
Rocked by violence in capital Tashkent in 2004
Government says radical Islamic groups behind violence
US state department spokesman Richard Boucher said on Tuesday that the US and other countries were "increasingly organised and increasingly persistent" in their demands for an investigation.
Uzbek authorities say 52 people remain in custody.
Andijan's chief prosecutor said on national television that the group was being held on suspicion of organising terror and bandit attacks.
Those in detention include Saidjahan Zainabiddinov - a well-known human rights activist who stayed close to Andijan's main square after the crackdown began, helping journalists and telephoning foreign embassies.
China said on Tuesday it agreed with President Karimov's use of force.
"We firmly support the crackdown on the three forces of separatism, terrorism and extremism by the Uzbekistan government," Chinese foreign ministry spokesman Kong Quan told a news conference in Beijing.
"We support the efforts by the Uzbekistan government to stabilise the domestic situation and to engage in national development."
The Uzbek leader is due to meet Chinese President Hu Jintao and Prime Minister Wen Jiabao during his visit, which ends on Friday.