BEIJING, Nov. 26 -- An international campaign to save the life of a Chinese businessman sentenced to death after being convicted of spying for Taiwan may have been a factor in the Chinese government's apparent decision to delay his execution by at least a day, although he could still be put to death in Beijing as soon as Friday.

Word of the apparent delay in Wo Weihan's execution came the same day that the Chinese government carried out a high-profile execution, putting to death Yang Jia, who had been convicted of killing six Shanghai policemen. Yang's case had caused an unusual outcry in a country where support for capital punishment is generally strong.

Both cases have prompted concern at home and abroad about China's recent commitment to legal reform, with critics noting deviations from what they say should be basic legal procedure: defendants denied access to their attorneys, evidence withheld from defense lawyers, closed-door trials. China's highest court began reviewing all death sentences last year as part of that reform.

Wo's case marks "the first time ever that China has had to contend with an international campaign to stop an execution before it happens," said John Kamm, executive director of the Dui Hua Foundation, a human rights group in San Francisco. The United States and the European Union have led the campaign, with the Europeans especially concerned that China might carry out an execution even as their representatives are in Beijing to continue talks on human rights.

Until Wednesday, those involved had assumed from watching prior cases that Wo would be executed shortly after his family was allowed to visit him Thursday morning. But according to an official at the U.S. Embassy, a Chinese official informed the French Embassy late this afternoon that "there would not be an execution Thursday." It is unclear whether that represents a stay of execution related to the campaign to save Wo or merely a later execution date.

Wo, 60, was sentenced to death after he allegedly confessed to passing sensitive information to the Taiwanese, a confession he retracted. He has been in custody since early 2005. China's Supreme People's Court had been reviewing his case for eight months, but officials from a lower court notified his family members last week that they should request permission to visit him, indicating that the review had been completed and that the execution would be allowed to proceed.

Wo's family members had hired a lawyer but said she was barred from discussing details of the case with them because they are considered state secrets and to reveal them would be a separate crime.

Wo's wife and his daughter, Ran Chen, an Austrian citizen, will be allowed to visit him at 9 a.m. Thursday at the Second Intermediate People's Court in Beijing. They expect to be given 15 to 30 minutes, with prison officials present. Human rights groups, including Amnesty International, say Wo could be put to death at any time after the meeting.

Chen and her husband, Michael Rolufs, an American, have spearheaded the campaign to persuade China to spare her father's life. "We hope that China, as a modern and confident country, will consider our appeal," Chen said.

"Given the news today, I'm optimistic that they might commute the sentence," Kamm said, adding that there are provisions in Chinese law that would permit it.

The case of Yang, the convicted police killer, generated little attention outside China but unusually strong opposition at home. Yang was executed by injection in Shanghai on Wednesday morning after the Supreme People's Court upheld his death sentence last Friday. The 28-year-old unemployed Beijinger had stormed a Shanghai police station in July and fatally stabbed six police officers. He was convicted on all six counts.

Yang's mother, Wang Jingmei, who was apparently illegally detained in a Beijing mental institution for the four months her son was on trial, says authorities never told her Sunday when they escorted her to see her son that it would be her last visit with him. She also said she was not told of the decision to carry out the death sentence until the night before.

"The way this turned out made a lot of people feel desperate, not because Yang Jia was executed but because there's a serious violation of law in terms of the legal procedure," Liu Xiaoyuan, a lawyer retained by Yang's father, said Wednesday.

In a surprising twist, many Chinese had come to view Yang as a hero who had dared to stand up to police brutality and abuse of power after he told the news media that he killed the policemen to avenge their mistreatment of him during questioning about a stolen bicycle.

Yang's father was more restrained. "I don't agree with what Yang Jia did," he said. "He's not a hero. People shouldn't be idolizing him."

"But during all this, I have learned one thing for sure about our country," he added, "and that is that you are not allowed to tell the truth. Even if you do, no one will pay attention to you. I wrote so many letters and got no response. I am a father and a Chinese citizen. The least my government could do was give me some response."

Researcher Liu Songjie contributed to this report.