Washington, Aug 25 - As much as half the American population could be infected with swine flu and it could kill up to 90,000 people, The Washington Post quoted a presidential panel as saying Tuesday.

The Post cited an estimate from the President's Council of Advisors on Science and Technology to say that 'the virus could cause symptoms in 60 million to 120 million people, more than half of whom might seek medical attention'.

Although most cases probably would be mild, up to 300,000 people could require intensive care, the council observed in its 86-page report submitted to the White House.

'This is going to be fairly serious,' Harold E. Varmus of Memorial Sloan-Kettering Cancer Center in New York, co-chair of the 21-member council, was quoted as saying. 'It's going to stress every aspect of our health system.'

It is the first time experts have released specific calculations about the possible impact of the pandemic in the US.

Swine flu or Influenza A (H1N1) emerged last spring in Mexico and quickly spread to the US and around the world. The virus has sickened children and young adults more frequently than the typical seasonal flu.

The 'plausible scenario' is based on previous pandemics and how the swine flu behaved in the US and during the Southern Hemisphere's winter over the past few months, said Marc Lipsitch of the Harvard School of Public Health who helped prepare the estimate.