BEIJING >> An American human rights envoy said Thursday that China provided no useful information when probed about specific cases of individuals who have been detained or who disappeared in a major crackdown on dissent in recent months.

Hundreds of lawyers, activists, and other intellectuals have been questioned, detained, confined to their homes or have simply disappeared, apparently to squelch any chances of the kind of popular uprisings roiling the Middle East and North Africa. The clampdown on dissent is the broadest and harshest in years by China’s Communist government.

Michael Posner, U.S. assistant secretary of state for democracy, human rights and labor, said that his delegation received no satisfactory answers to its questions about Teng Biao, a law professor who disappeared in February, and the artist Ai Weiwei, who was apparently detained by authorities April 3 but has yet to be formally charged.

"We need to and will continue to raise these issues in a range of forums," Posner said. "The most senior government officials in the United States are deeply concerned about the deterioration of human rights in China over the last several months."

Posner said he also asked about cases that predate the latest crackdown.

The U.S. delegation requested information about the whereabouts of the prominent human rights lawyer, Gao Zhisheng, who has been missing for a year, and the well-being of Liu Xia, a poet and painter who is married to Nobel Peace laureate Liu Xiaobo and who has been under house arrest since her husband was awarded the prize.

Posner described the talks as "respectful in tone."

"It was not a discussion where there were voices raised, but it was a discussion that was very much based on the facts, and the facts are not good," he said.

The two sides had frosty exchanges ahead of the closed-door talks, with the U.S. saying it would focus on the ongoing campaign against dissent as well as on the rule of law, religious freedom and labor and minority rights.

China’s Foreign Ministry warned it would reject what it regards as U.S. meddling.

"We also are opposed to the United States using human rights as a pretext for interfering in China’s internal affairs," spokesman Hong Lei said at a regularly scheduled briefing Thursday.

Posner said he disagreed with those who characterized U.S. concern as meddling.

"This is not about us, it’s about the Chinese people and their relationship to their government," he said.

Beijing defines human rights primarily in terms of improving living conditions for its 1.3 billion people and maintains strict controls over free speech, religion, political activity and independent social groups.

A defiant editorial in the Communist Party-run Global Times newspaper on Thursday said China would never allow the U.S. to dictate political reforms and claimed that most Chinese "were disgusted" by outside pressure on human rights.

"As China is a sovereign nation, there is zero possibility of it allowing the U.S. to dictate its political development," it said.

In a sign of the ongoing intimidation of dissident voices, a rights group said that police in the eastern province of Jiangsu had detained singer Zuoxiao Zuzhou and sports writer Zhang Xiaodan for 12 hours of interrogation after they led fans at a music festival in calls for the release of Ai, the detained artist.

Zuoxiao and Zhang were released Thursday, media reports and the Hong Kong-based Information Center for Human Rights and Democracy said.