Hong Kong (CNN) -- China's bird flu crisis showed no sign of easing Tuesday as the death toll rose to nine, a government agency said.
The National Health and Family Planning Commission announced two more fatalities Tuesday afternoon -- one in Anhui province and the other in Jiangsu province.
These are the first bird flu-related deaths reported this year in those two provinces. Five deaths -- and just less than half of the 28 confirmed infections nationwide -- have been in Shanghai, according to the Chinese commission.
The virus had been found in pigeons but had not previously been discovered in humans until a series of cases were reported in China last week.
In Shanghai, more than 100,000 live birds have been killed in the past week at live-poultry markets across the city in an effort to contain the problem, the Shanghai Municipal Ministry of Agriculture said. A number of cities across China have also announced trading suspensions.
During a news conference in Beijing on Monday, World Health Organization and Chinese health ministry officials tried to reassure the public about the outbreak, saying they would continue to jointly monitor the behavior of the virus.
"Although we do not know the source of the infection, at this time there is no evidence of sustained human-to-human transmission," said the WHO's Michael O'Leary.
The Chinese health agency also said Tuesday that there are no reported cases of human-to-human transmission.
Liang Wannian, director of the H7N9 influenza prevention and control office under the National Health and Family Planning Commission, told reporters that 621 close contacts of infected patients had been monitored with no reported abnormalities.
Meanwhile, Chinese Vice Premier Liu Yandong called for further efforts to prevent the spread of H7N9 infections and the treatment of patients after visiting the country's disease control center on Monday, Xinhua reported.
She also urged more transparency in information about the virus and said any new infection should be discovered, reported, diagnosed and treated as early as possible. She added that President Xi Jinping and Premier Li Keqiang were paying close attention to the crisis.
CNN's Ke Feng in Beijing contributed to this report.