BEIJING - Two patients from East China's Anhui and Jiangsu provinces who were confirmed as H7N9 cases days ago died of the avian influenza on Tuesday afternoon, said health authorities.

This has brought the total number of deaths caused by the H7N9 bird flu in the country to nine, the National Health and Family Planning Commission announced in a daily update on H7N9 cases across China.

The agency also said that, during the 25-hour period ending 6 p.m. on Tuesday, China has confirmed four new cases of H7N9 avian influenza, with two each in east China's Zhejiang province and Shanghai city.

China officially confirmed the occurrence of human infection with the H7N9 virus late last month.

So far, China has reported a total of 28 H7N9 cases, including nine which ended in fatalities.

A total of 13 cases, including five ending in fatalities, have been reported in Shanghai. Eight cases, including one death, have been reported in Jiangsu, and two cases, including one death, in Anhui. Five cases have been reported in Zhejiang, with two deaths.

No epidemiological link between those cases has been identified to date, the agency said, adding that those who have had close contact with people infected by H7N9 have been placed under medical observation.

It said the country's confirmed H7N9 cases were isolated and there has been no sign of human-to-human transmission.