WASHINGTON -- President Obama went golfing and the Department of Health and Human Services is short a secretary, so other U.S. officials took the controls Sunday as the Obama administration ramps up efforts to find and isolate U.S. cases of swine flu.
During a White House briefing, Homeland Security Secretary Janet Napolitano announced that HHS will issue a public health emergency warning that will free up resources to address the outbreak that has hit 20 Americans in five states.
Richard Besser, acting head of the Centers for Disease Control and Prevention, said the agency is prepared to move millions of doses of the U.S. anti-virus stockpile to areas of early and potential outbreaks.
Besser said the flu's spread is in its early stages and the current situation is "extremely unpredictable." He said the government will provide "daily" updates on the number of confirmed cases and provide advice and intervene at the local level as conditions warrant.
"As we continue to look for cases, we are going to see a broader spectrum of disease," Besser said. "We're going to see more severe disease in this country."
Meanwhile, as Napolitano, Besser, presidential homeland security adviser John Brennan and White House spokesman Robert Gibbs addressed reporters, Obama golfed with Commerce Secretary Gary Locke, Trade Representative Ron Kirk and White House aide Marvin Nicholson.
The White House permitted journalists no opportunity to video Obama golfing. Gibbs denied that the rare weekend White House briefing was designed to minimize attention that otherwise might have been paid to a presidential golf outing during a public health scare.
"I'm not sure I would draw a direct conclusion between the news today and the president's golf," Gibbs said. "The president has been updated regularly on this and will continue to do so as we will continue to regularly update you."
Napolitano said the emergency announcement is designed to increase preparations to combat and isolate swine flu, not to create public alarm. She said such health emergencies had recently been issued to deal with flooding in Minnesota and North Dakota and for Obama's inauguration.
"That sounds more severe than really it is," Napolitano said. "This is standard operating procedure and allows us to free up federal, state and local agencies and their resources for prevention and mitigation and allows us to use medication and diagnostic tests that we might not otherwise be able to use, particularly on very young children, and it releases funds for the acquisition of additional anti-virals."
Ordinarily, such an announcement would have been made with the secretary of Health and Human services present. But Obama's nominee, Kansas Gov. Kathleen Sebelius, is still awaiting confirmation from the U.S. Senate, which is expected to vote this week.
Gibbs said the effort to get a team in place to respond to the health scare has not been hindered by the lack of a secretary at HHS, a vacancy in the surgeon general's post or the acting roles for the heads of the Food and Drug Administration and CDC.
"I think this notion somehow that if there's not currently a secretary that there's not the function that needs to take place in order to prepare for either this or any other situation is just simply not the case," Gibbs said.
"I think these guys have given you a pretty good indication of the response mechanisms that are in place and that have been activated relating to this, so, I think it's all-hands-on-deck and we're doing fine.
"I would say we're hopeful that we have a new secretary very shortly," he added.
Despite the opening at the top of HHS, Napolitano's role as homeland security chief gives her the top authority in nationwide coordination.
Napolitano said reports from the Agriculture Department show no threat to the U.S. food supply. She reminded Americans that swine flu cannot be transmitted by eating pork.
The current virus appears to be a combination of four flu strains: the North American swine virus, the North American avian virus and a combination of human and swine viruses from Europe and Asia.
Napolitano said there was no indication of bio-terrorism and the virus appears to be a natural phenomenon.
She said the United States will use a "passive screening protocol" at the border through border control agents and Transportation Security Administration personnel to ask passengers from Mexico if they are sick, if they've recently been sick or if they demonstrate any visible symptoms of swine flu.
Passengers will not be barred from entry if they meet any of the swine flu screening criteria, but they may be referred for additional medical testing.
"Right now we don't think the facts warrant more active testing or screening of passengers coming in from Mexico," Napolitano said.
The State Department has not issued any travel restrictions from the United States to Mexico but is continuing to evaluate the public health risk.
The outbreak of swine flu in Mexico has affected nearly 1,614 people, including killing as many as 103. Besser said the Mexican authorities shared with the United States news of confirmed cases "immediately," and the U.S., Canada and Mexico have had "great collaboration" on testing possible infections.
"I'm in daily communication with their public health leadership and the collaborations have been absolutely superb. We share information about what we're seeing here, and they're sharing information about what they're seeing in Canada and in Mexico," Besser said.
Obama was in Mexico City on April 16-17, and not has exhibited any symptoms of flu, Gibbs said, noting that doctors report the incubation period for swine flu is 24 to 48 hours.
Gibbs appeared to contradict White House domestic policy adviser Valerie Jarrett, who earlier in the day said the president is fine after being asked whether he had been tested.
"When I checked yesterday, he had not been," Gibbs said. "Again, based on the incubation period, neither he nor anybody that he traveled with nor anybody in the press corps that I'm aware of would have exhibited any symptoms that would have caused any heightened awareness.
"I think this probably goes without saying, too, in the absence of symptoms, you shouldn't go get tested. That is going to crowd any sort of either public health or private health infrastructure," Gibbs added.
Napolitano said the government has 50 million doses of Tamiflu and Relenza, the two drugs that can treat the current swine flu virus, on hand and will soon move 25 percent -- or 12.5 million doses -- to states with confirmed cases of the disease.
Besser said the 20 cases of flu that have been confirmed include eight in New York City at St. Francis Prepatory School; seven in California; two in Texas; two in Kansas and one in Ohio.
Besser said all of the cases have been classified as mild and that only one person sickened by the flu has required hospitalization.
The Associated Press reported that Canadian officials confirmed midday Sunday swine flu had reached the province of Nova Scotia. Four students from King's-Edgehill School in Nova Scotia contracted "very mild" cases of the flu and are recovering, said Chief Public Health officer Dr. Robert Strang. None of the students, ages 12 to 18, have been hospitalized, he said. Details were pending on the other two confirmed cases.
FOX News' Major Garrett and FOXNews.com's Sharon Kehnemui Liss contributed to this report.