Activists were calling on President Barack Obama to cancel Chinese President Xi Jinping’s upcoming visit to the United States, citing an ongoing crackdown on human rights lawyers and activists in China that has worsened steadily under Xi. In four days, more than 60 Chinese human rights lawyers and activists “have been forcefully taken away by the police or ‘disappeared,’” the petition, filed on the White House’s website, said. “The number is still rising,” it added, stating that more than 1,000 political dissidents have been arrested during Xi’s rule.

“Xi’s state visit to the U.S. scheduled for September this year should be cancelled, and all official exchanges with the Chinese government should be suspended until this matter is resolved,” the petition concluded. As of Tuesday afternoon, 1,610 people had signed the petition, out of a goal of 100,000 signatures by Aug. 10.

Between last Thursday and Tuesday morning, nearly 150 lawyers and activists were arrested or questioned, many of whom had signed a letter demanding the release of Wang Yu, a lawyer who handled politically controversial cases and was arrested early Thursday, the Guardian reported.

GettyImages-466018928 Paramilitary police officers stopped a woman as she protested on her knees in front of the Great Hall of the People, as the annual session of China's legislature, the National People's Congress, was held, in Beijing, March 13, 2015. Photo: Greg Baker/AFP/Getty Images

Lawyers who take on cases defending free speech and human rights or targeting abuses of power were the primary targets of the crackdown, the BBC reported, citing a statement from the Ministry of Public Security. About 50 lawyers had been detained or questioned by police in Beijing, Shanghai and Guangzhou as part of the crackdown.

"Such an unprecedented nationwide crackdown can only have been sanctioned from within the central government," William Nee, a China researcher at Amnesty International, said, the BBC reported. "This coordinated attack on lawyers makes a mockery of President Xi Jinping's claims to promote the rule of law." 

China’s record on human rights has declined considerably under Xi, a report published in October by the U.S. Congressional-Executive Commission on China found, with Beijing's authoritarian government increasingly limiting free speech and human rights, it noted. Xi became leader of China's Communist Party in 2012 and the country's president in 2013. 

The U.S. government said it had taken note of these events “with growing alarm,” according to a statement from a State Department representative. “‎We are deeply concerned that the broad scope of the new National Security Law is being used as a legal facade to commit human rights abuses. We strongly urge China to respect the rights of all of its citizens and to release all those who have recently been detained for seeking to protect the rights of Chinese citizens,” the statement added.