WASHINGTON, April 26 (Reuters) - The United States is stepping up efforts to monitor and respond to a swine flu outbreak that has claimed as many as 81 lives in Mexico. U.S. officials held a rare Sunday briefing at the White House to outline the administration's response. Here is a summary of what they had to say:
* Twenty cases of the new strain of swine flu have been confirmed in the United States -- one in Ohio, two in Kansas, eight in New York.
* All U.S. cases have been mild with no deaths, but more cases are expected.
* The virus strain is new and there is not vaccine at this point for it.
* Officials are declaring a public emergency to ensure proper government preparation in case the outbreak broadens
* U.S. health officials recommend planning for potential U.S. school closures due to outbreak.
* Officials are unsure how much of an outbreak to expect.
* President Barack Obama is being updated regularly on the outbreak and U.S. officials have put in place a "robust" communications system to monitor outbreaks and disseminate information. The administration plans daily briefings.
* Homeland Security Secretary Janet Napolitano says the outbreak does not warrant testing of airplane travelers from Mexico. She said officials were doing "passive surveillance" at this point.
* U.S. to release some of its 50 million treatment courses of Tamiflu and Relenza from its strategic stockpile.
* Officials said there is nothing to link the outbreak to a possible terrorism attempt and that there was nothing in the investigation to suggest anything but "a naturally occurring event." (Editing by Maggie Fox and Patricia Zengerle)