AFP - US President Barack Obama should "pick up the phone" and urge Chinese President Hu Jintao personally to ease pressure on a Beijing-based human rights lawyer, Jiang Tianyong, US lawmakers said Monday.

Jiang, who sought in vain to meet with Obama during the US president's recent visit to China, was detained and interrogated by Chinese officials and is now at home under heavy police surveillance, they said.

"The president should pick up the phone and call Hu Jintao and say 'do not hurt this man, or any others like him,'" said Republican Representative Chris Smith, a long-time critic of Beijing's rights record.

And the US Ambassador to China, Jon Huntsman, "should get in the car and drive over to his (Jiang's) house and stand with him," said Republican Representative Frank Wolf.

Smith and Wolf, backed by Chinese dissidents Harry Wu and Wei Jingsheng, criticized Obama for not doing enough to raise the issue of human rights during his maiden visit last week to China as president.

"The United States must stop decoupling human rights from its strategic dialogue," said Wu.

Noting that the White House said Obama had raised the issue in private talks with Hu, Wei said through an interpreter that "you should not talk in private, you should put this above the table."

Smith dismissed Obama's approach as "smile and use soothing words to get your way," calling it "naive" and warning "if you're going to partner with an egregious human rights abuser, you get tainted, the White House gets tainted."

"Hopefully, you know, hope springs eternal, the president will pivot and realize the folly of his current trajectory and speak out and this is the perfect place" and time to do so, said Smith.

A senior Obama administration official said it raised Jiang's case with China, "expressing our concern for his welfare, opposing his detention and urging his immediate release."

"These actions raise serious concerns about (China's) stated commitment to the rule of law," the official said on condition of anonymity.

Jiang, visiting Washington ahead of Obama's trip, told AFP in an interview that the president should not shy away from discussing human rights, saying that the issue was coming into mainstream conversation in China.

"Obviously 'human rights' carries a different connotation than in the international sense," Jiang said. "But if China can talk about it, then why can't the president of the United States?"