The number of COVID-19 patients detected in Xi'an, Shaanxi province, significantly dropped on Tuesday, an indication that the strict prevention and control measures previously introduced have achieved results, a senior official said on Wednesday.

Xu Mingfei, vice-mayor of Xi'an, said the three rounds of mass nucleic acid testing and screening conducted recently showed the number of detected patients is trending downward after great efforts were made and effective measures taken.

Xi'an reported 35 confirmed cases on Tuesday, compared with 95 on Monday, 90 on Sunday and 122 on Saturday.

As of the end of Tuesday, Xi'an has reported a total of 1,793 confirmed cases, with 37 having been cured and discharged from hospitals, Xu said.

The newly reported patients on Tuesday were all detected among people who have been put under quarantine and in the areas that have been sealed off for strict management, he said.

Despite the drop in cases, Xu urged relevant departments not to relax their vigilance in the weeks to come as the city is still in a critical period in its fight against the epidemic.

"The novel coronavirus usually has an incubation period of two weeks, and about 42,000 residents are still being placed under quarantine in Xi'an," Xu said.

Lyu Yongpeng, deputy director of the Xi'an health commission, said all the new patients detected on Tuesday developed only mild symptoms.

To block the spread of the novel coronavirus in local communities, the city started a new round of testing at 9 am Tuesday. By 9 am on Wednesday, samples had been collected from 12.7 million residents, Lyu said.

Xu said medical institutions in the city are required to set up hotlines and green channels for pregnant women, critically ill patients, and those going through dialysis, radiotherapy and chemotherapy.

"No medical institutions are allowed to refuse these patients in the name of curbing the spread of the novel coronavirus," he said.

The remark came after a much-discussed social media post where a woman in the city alleged that she had a miscarriage after failing to be admitted to a hospital in time due to expired nucleic acid test results. The local women's federation said relevant departments have begun to investigate the case.

Liu Jun, former director of the Xi'an Bureau of Big Data Resources, was suspended due to his failure to perform his duties in the fight against the outbreak, local authorities said on Wednesday morning. The move came after the city's health code system crashed twice recently.

A senior epidemiologist has called on people nationwide to support Xi'an.

"The COVID-19 outbreak in Xi'an is the most serious one in China since the one in Wuhan in Hubei province at the beginning of 2020, and people all over the country should strongly support the city in its efforts to fight it," said Zeng Guang, former chief scientist of epidemiology at the Chinese Center for Disease Control and Prevention, on Tuesday.

He told media that the outbreak was caused by the Delta variant, which spreads faster than the strain that hit Wuhan.

"The task is arduous, as the transmission chain has multiple links and moves in secret," said Zeng, who is also a member of the National Health Commission's senior-level expert panel.

Zeng said he hoped Xi'an authorities will learn more about containing the spread of the coronavirus and share their experience with other regions.

Kang Ruoming contributed to this story.