“Unmistakable evidence exists that this devastating epidemic is not an occurrence of nature but the work of anti-American extremists, operating within our own borders but supported by our enemies abroad,” Hughes told an anxious nation. “This is a crime not only against the people of the United States but against all humanity.”

His speech came after a day when the first cases of the illness were reported in neighboring states, just hours after Hughes ordered Colorado’s borders closed and placed the nation’s military on high alert. All domestic and international air travel was also grounded by presidential order, leaving the nation’s transportation hubs in turmoil, as thousands of stranded travelers sought other means to get home.

Seeking both to reassure the country and counter growing criticism that his administration has been slow to act on the crisis, Hughes told the nation to prepare for a formidable struggle.

“I ask you tonight for your trust, your resolve, and your prayers,” the president told the country. “We will leave no stone unturned. Justice will be swift.”

The president did not specify which groups or nations were the targets of federal scrutiny. He also declined to elaborate on the nature of any evidence the administration had uncovered to indicate the epidemic is the work of terrorists.

Presidential spokesman Tim Romer, when asked about a possible military response, told reporters, “We’re ruling nothing out at this point.”

Reports from local officials inside the state indicate that as many as fifty thousand people may have died already. It is unclear how many of the victims succumbed to the disease itself and how many were slain by violent attacks at the hands of those infected. Early signs of exposure include dizziness, vomiting, and a high fever. After a brief incubation period—as short as six hours—the illness appears, in some cases, to bring about a marked increase in physical strength and aggressiveness.

“Patients are going crazy and killing everybody,” said one Colorado health official, who asked to remain anonymous. “The hospitals are like war zones.”

Shannon Freeman, spokesman for the Centers for Disease Control in Atlanta, downplayed these reports as “hysteria” but conceded that communication with officials inside the quarantine zone had broken down.

“What we know is that this illness has a very high fatality rate, as high as fifty percent,” said Freeman. “Other than that, we can’t really tell what’s going on in there. The best thing anyone can do for the moment is stay indoors.”

Freeman confirmed reports of outbreaks in Nebraska, Utah, and Wyoming, but declined to elaborate.

“That appears to be happening,” she said, adding, “Anyone who thinks they have been exposed should report to the nearest law enforcement official or hospital emergency room. That’s what we’re telling people at this point.”