WASHINGTON, Feb. 9 (Xinhua) -- Flu activity continued to increase across the United States, making this winter's flu season the most recent "high" severity season, a U.S. health official said Friday.

"We may be on track to break some recent records," Anne Schuchat, acting director of the U.S. Centers for Disease Control and Prevention (CDC), told reporters on a conference call.

A total of 10 children were reported dead due to flu during the week ending on Feb. 3, making its total deaths 63 this winter, according to CDC's weekly data.

A cumulative rate of 59.9 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported, higher than those in last week, it said.

The highest rate of hospitalization was among adults aged above 65 years followed by adults aged 50 to 64 and children aged 0 to 4 years.

Among the hospitalizations, over 86.4 percent were associated with influenza A virus, over 13.2 percent with influenza B virus, and some with influenza A virus and influenza B virus co-infection.

Schuchat said it was uncommon for B strains to increase later in the season, and there might be a second wave of influenza B infections.

The spread of influenza in 48 states and Puerto Rico was reported as widespread, according to CDC.