The United States on Thursday pressed China to improve its deteriorating human rights record ahead of the September state visit to Washington by President Xi Jinping.
Top of the US long list of concerns raised at a human rights dialogue was a crackdown on public interest lawyers and proposed legislation to police non-government organizations.
Assistant Secretary of State Tom Malinowski said there's a "growing sense of alarm" in the US government over such developments and the direction China is heading as it seeks to combat "cultural infiltration" from the West.
He said the dialogue was a chance "to stress the importance of making specific improvements if the Chinese side wants the tone and the substance of the summit to be positive."
The head of the Chinese delegation, senior Foreign Ministry official Li Jinhua, was due to hold a separate news briefing at the Chinese Embassy Friday.
US lawmakers this week have been calling for President Barack Obama to make sure human rights is not crowded out of the agenda when Xi makes his first White House visit since taking power in 2013. Cyber security, maritime security, economy and trade, and climate change all demand attention.
Malinowski described Thursday's discussions, joined by a range of government agencies on both sides, as "very detailed and substantive" but said there were "very profound differences."
He said the Chinese side raised police violence in the United States, such as the shooting death a year ago of Michael Brown, an unarmed black man, by a white police officer in Ferguson, Missouri, where unrest has flared again this week. But he added the vast majority of the conversation was on the situation in China.
The US says more than 250 attorneys, activists and their family members detained, interrogated and held incommunicado in the recent crackdown, and some forced to make televised confessions. Most have been released.
Malinowski called for the immediate release of several lawyers still held, among them Wang Yu, Zhou Shifeng, Li Heping and Li Xiaoyuan. He said while China has been emphasizing the rule of law in its public rhetoric, "it's hard to have rule of law when lawyers are being arrested for doing their jobs."
The US is also calling for China to shelve or significantly revise a proposed law on non-government organizations that it says could jeopardize a large array of US engagements in the country.
Human rights activists have voiced skepticism about the efficacy of the dialogue, last held in 2013.
Malinowski said the fact that China was willing to take part showed that it cares about its international image. He said the Chinese side acknowledged that human rights issues would be discussed in a "prominent way" at the Obama-Xi summit.
"We will see how they respond," he said.
The US also raised concern over restrictions on American journalists, academics and US diplomats in China, and curbs on religious freedom in Tibet and the far western region of Xinjiang, and a government campaign to remove crosses and demolish Christian churches in Zhejiang province.