A U.S. presidential advisory group says in a new report that the A-H1N1 swine flu virus "poses a serious health threat" to the nation.

The President's Council of Advisors on Science and Technology says that although the government's effort to prepare for the flu season later this year has been well-organized and scientifically grounded, some preparations should be improved.

In the report released Monday, the independent group of scientists says the government needs to accelerate the preparation of flu vaccine for distribution to high-risk individuals.

The group also says the government needs to upgrade the current system for tracking the pandemic's progress.

But overall, the scientists say they are "deeply impressed" by the high level of cooperation among government agencies preparing for the expected resurgence of the virus in the coming months.

The World Health Organization has declared the swine flu outbreak a pandemic and says up to two billion people may eventually be infected.

The WHO says the flu strain has killed nearly 1,800 people worldwide.

Some information for this report was provided by Reuters.