The World Health Organisation(WHO) says there have been more than 700 deaths from swine flu since the start of the outbreak.
The figure is an increase of some 300 since the start of the month.
The global body says it doesn't know how many cases there are worldwide because it stopped asking countries to report infections last week.
WHO spokeswoman Aphaluck Bhatiasevi says the Geneva-based agency is examining various measures countries can take to slow the spread of the disease.
She told reporters Tuesday that school closures could be among the recommendations but that it was up to each country to consider appropriate steps for their situations.