The White House says President Barack Obama has declared swine flu a "national emergency" as the United States reels from millions of cases of infection and over 1,000 deaths. The emergency declaration, signed by the president late on Friday, enhances the ability of medical treatment facilities to handle a spike in influenza A(H1N1) patients by allowing medical officials to temporarily bypass certain federal requirements.

"The 2009 H1N1 pandemic continues to evolve," Obama said in the declaration.

"The rates of illness continue to rise rapidly within many communities across the nation, and the potential exists for the pandemic to overburden health care resources in some localities."

The declaration comes just days after Health Secretary Kathleen Sebelius warned that demand is outstripping supply of vaccine for the novel flu strain.