Two more people have died in China from a new strain of bird flu, raising the death toll from the virus to 13, state media has reported.

The official Xinhua News Agency said on Sunday the two deaths were reported in Shanghai and that three new cases were also confirmed in the financial hub.

A total of 11 new cases were reported on Sunday - including two in a central province that previously had been unaffected. In all, 55 cases of the virus, known as H7N9, have been reported in China.

The latest cases in central Henan province, which is next to Beijing, followed an announcement on Saturday that a seven-year-old girl had become the first person in the capital to be infected with the virus.

'No surprise'

All previous reported cases were in Shanghai and other eastern areas of the world's most populous country.

A World Health Organisation official has said that it was not surprising that the virus had spread to Beijing.

Michael O'Leary, head of WHO's office in China, said it's not the case that everyone confirmed to be infected with H7N9 was "clustered in one small area with the same source of exposure".

"So we've been expecting new cases to occur .... Furthermore, we still expect that there will be other cases," he said.

Health officials believe the virus, which was first spotted in humans last month, is spreading through direct contact with infected fowl.

O'Leary said "the good news" was that there was still no evidence that humans had passed on the virus to other humans.

"As far as we know, all the cases are individually infected in a sporadic and not connected way," he said, adding that the source of infection was still being investigated.

The girl from Beijing, whose parents are in the live poultry trade, was admitted to a hospital on Thursday with symptoms of fever, sore throat, coughing and headache, the Beijing Health Bureau said.

China has been more open in its response to the new virus than it was a decade ago with an outbreak of SARS, when authorities were highly criticised for not releasing information.

Source: Agencies