A dissident at the center of a standoff between Beijing and Washington on Tuesday accused Chinese authorities of a pattern of abuse against his family as he again took his case to US lawmakers.

Chen Guangcheng, a blind self-taught lawyer who last month dramatically escaped house arrest for the safety of the US embassy, telephoned a hearing of the US Congress for the second time this month from a hospital bed in Beijing.

Unlike in the previous hearing, Chen did not voice concern over his own conditions. But he charged that local authorities in the eastern province of Shandong were seeking revenge by filing a murder charge against his nephew.

"These are trumped-up charges. Those people in Yinan county have already been on the opposite side of the rule of law in China," Chen said by telephone as one of his most prominent supporters, Chinese dissident Bob Fu, translated for members of the House Foreign Affairs Committee.

Chen said government-backed thugs broke into his nephew Chen Kegui's house and beat him up for three hours with stakes until his face was bloody, with police detaining him when he fought back. Despite the murder charge, no one was reported dead.

"This is a pattern," Chen said, accusing authorities of launching the same sort of campaign against his nephew as they did to him. Chen served four years in jail on charges that included disruption of traffic.

Chen had riled authorities by exposing forced abortions and sterilizations by officials meeting quotas under China's one-child-only policy. Chen has said he was subjected to brutal beatings under house arrest because he continued to speak out after his release from jail in 2010.

In a striking scene on Capitol Hill, Chen spoke to Representative Chris Smith, a longtime campaigner against China's one-child policy, as some of China's leading exiled dissidents -- including legendary activist Wei Jingsheng and Tiananmen Square protest leader Chai Ling -- huddled on the dais to listen.

After Chai Ling -- now an advocate against sex-selective abortion -- praised his efforts, Chen replied: "I'm not a hero. I just do what my conscience asks me to do."

"I cannot be silent and cannot be quiet when facing these evils against women and children, and so this is what I should do," Chen said.

Chen broke several bones in his foot as he climbed walls to escape house arrest, and then undertook a risky journey by car to Beijing, where he later sought refuge at the US embassy.

US officials escorted him to a hospital on May 2, saying that China had made assurances for his safety.

But Chen telephoned a congressional hearing a day later, saying he feared for the safety of himself and his family. He said he wanted to leave for the United States and appealed for a meeting with Secretary of State Hillary Clinton, who was visiting Beijing.

State Department officials, faced with strong criticism by lawmakers and Republican presidential contender Mitt Romney, said that Chen had never requested asylum but changed his mind after leaving US protection.

Under a second deal, US officials said that China had agreed to allow Chen to travel soon to the United States.

State Department spokeswoman Victoria Nuland said Tuesday that US visas were prepared for Chen, his wife and their two children.

"We are ready when he and his government are ready," Nuland told reporters.

The State Department has preferred behind-the-scenes diplomacy to resolve Chen's case, fearing outright criticism of China would backfire.

But five senators on Tuesday released an open letter to Chinese President Hu Jintao voicing "deep concern" over the safety of Chen and saying that human rights improvements were vital for better relations between the Pacific powers.

"We urge your government to seize this opportunity to end the harassment of rights advocates and embark on a new path towards greater respect for human rights in China," it said.

The letter was signed by Republicans Marco Rubio, James Inhofe and Jim DeMint and Democrats Sherrod Brown and Robert Menendez.