The Chinese researcher said he edited a gene of a human embryo, later implanted into a woman who gave birth to the twins, one of whom is HIV immune.
China's Vice Minister of Science and Technology has condemned the "unacceptable" research, and said ministry is strongly opposed to the reported experiments.
Chinese people "have a high willingness to use of gene in disease prevention and treatment", Liang Chen, a professor at Sun Yat-Sen University, was quoted as saying.
Xu said the ministry had ordered authorities to suspend all scientific activity of people involved with the case and mete out punishments after an ongoing investigation.
He said gene editing would help protect the girls from HIV, the virus that causes Aids.
More than 100 scientists signed a petition calling for greater oversight on gene editing experiments. As a result many mainstream scientists thinks it's too unsafe to risk trying and some have denounced this report as human experimentation.
China's National Health Commission said on Monday it was "highly concerned" and had ordered provincial health officials "to immediately investigate and clarify the matter".
They say there are serious unanswered questions about the safety of embryo editing and a need to make sure that such research is conducted in a transparent, monitored way so the technology is not misused.
Conference leaders called for an independent investigation of the claim by He Jiankui of Shenzhen, who spoke to the group Wednesday as worldwide criticism of his claim mounted.
"Even if the modifications are verified, the procedure was irresponsible and failed to conform with worldwide norms", the organizers said in the summit's consensus statement that is usually seen as setting the tone and direction for the fast-changing field. They had HIV positive males and HIV negative mothers.
The pioneer of improving versions of CRISPR and professor at Harvard University of chemistry and chemical biology, David R Liu, said, "There's a faily tight consensus from what is and is not acceptable in genome editing as of now, and He's reported work represents a departure from that".
Dr He Jiankui's experiment to alter the DNA of twin babies - also known as germ line gene editing - means the changes in those genes could be passed on and inherited by the next generations.
"We care deeply about the two babies and appeal for the research and formulation of detailed medical and ethical care plans", it said.
However, many of those in attendance at the Hong Kong conference have pointed out that while He has not necessarily contravened any global regulations, his purported use of CRISPR represents a clear break with convention. "Its flaws include an inadequate medical indication, a poorly designed study protocol, a failure to meet ethical standards for protecting the welfare of research subjects, and a lack of transparency in the development, review and conduct of the clinical procedures", they said.
He acknowledged he had not made his university in China aware of the research he was doing.
For years, leading scientists have avoided advocating a ban on gene-editing technology for human reproduction, instead favoring a cautionary approach that such research should not proceed until certain conditions are met. He's PR representative said He will not accept interview requests from the media at present due to privacy concerns, but that he will release a statement in the days to come.