Health officials scrambled Monday to trace contacts who may have interacted with infected 2019 novel coronavirus patients across the country as four new U.S. deaths were reported, bringing the total number of fatalities on American soil to six.

The third, fourth, fifth, and sixth deaths were announced in Washington state, where two previous deaths were revealed over the weekend. Five of the deaths were in King County and one in Snohomish County, officials said.

“Unfortunately, we are starting to find more COVID-19 cases here in Washington that appear to be acquired locally here in Washington,” State health officer Dr. Kathy Lofy said during a press conference on Monday, as CNBC reported. “We now know that the virus is actively spreading in some communities.”

Meanwhile, in Texas, the saga of an infected patient being prematurely released in San Antonio sparked finger-pointing over alleged shortcomings in the federal government’s response to the deadly outbreak.

The evacuee from the virus’s epicenter in China was in the San Antonio community for more than 12 hours on Saturday, said Anita Kurian, assistant director of the Metropolitan Health District, in an interview with The San Antonio Express-News. During that period, Kurian said the patient rode a hotel shuttle to one of the region’s busiest retail outlets, North Star Mall, where she visited shops and ate at the food court from 5:30 to 7:30 p.m.

“We are making every effort to identify any exposures at the mall and based on what we have at this time, those exposures are pretty low risk,” Kurian said, recommending that the mall conduct a deep clean of its premises. At least 18 people at the Texas Center for Infectious Disease and three people at a Hampton Inn near the airport have been identified as potential low- and medium-risk exposures to the deadly illness.

There were 91 confirmed 2019 coronavirus infections in the U.S., including 43 picked up through the U.S. health system—in New York, Wisconsin, Florida, Rhode Island, Oregon, and elsewhere, according to a tally from the Centers from Disease Control and Prevention (CDC). Another 48 cases on American soil involved either repatriated individuals who were evacuated on State Department-chartered planes from China or the Diamond Princess cruise ship in Japan. Both Florida and Washington—where the outbreak has hit a nursing home—have declared public health emergencies.

A genetic analysis of the virus in Washington state suggests that the virus may have been spreading within the community for as long as six weeks before the first case was detected, The New York Times reported. That analysis was one of several indications that the infection has been spreading undetected as officials rushed to create a fast and effective test for its diagnosis.

Dr. Scott Lindquist, an epidemiologist for communicable diseases with the Washington State Department of Health, told the Times that he was aware of cases in the state where physicians suspected coronavirus but could not get those patients tested because of stringent CDC criteria. Lindquist added that he could not ballpark how many such cases there had been, but said the state laboratory was rapidly working to ramp up to performing 200 tests a day.

State health authorities said over the weekend that they planned to test residents and staffers at the Kirkland, Washington-based long-term care facility, where dozens of people in the most high-risk demographic for severe infection have reported symptoms.

“We’re really aggressively sampling in Washington State now, because we feel like it has been here and we haven’t had the ability to lab test,” Lindquist said.

Local officials and experts have previously called out the CDC for alleged missteps in handling the virus. Specifically, California physicians have said that they were hampered in identifying a positive patient because of the CDC’s stringent testing criteria, which until last week required a patient to have both respiratory symptoms and recent travel to China or contact with another known patient. Now the CDC is allowing tests on people with severe and unexplained respiratory illness with no known connections to other cases.

Texas Gov. Greg Abbott on Monday condemned the agency for what he called “negligence” in the San Antonio case.

Abbott asked the CDC to begin requiring three negative coronavirus results over 48 hours instead of its current requirement—two negative tests over 24 hours—to “ensure a course correction” for the mistake. After the San Antonio woman completed two negative tests, a third came back positive, the CDC said on Sunday night.

“What the CDC did is completely unacceptable,” Abbott said at a press conference on Monday morning. “It appears to be a case of negligence with regard to allowing this person who had coronavirus to leave Texas Center for Infectious Disease and go back into the general population. I think they understand the magnitude of the error.”

In a statement on Sunday, the CDC said the woman “was asymptomatic and met all of CDC’s criteria for release—resolution of any symptoms and two consecutive sets of negative test results, collected more than 24 hours apart.”

But the third test results came back “weakly positive” and triggered officials to put the patient back in isolation at a hospital after they had “some contact with others while out of isolation.”

“CDC and local public health partners are following up to trace possible exposures and notify them of their potential risk,” said a statement on Sunday. “It’s important to remember that this is a new virus and we are learning more about it every day. The cycle of infection… is not yet well understood, but the amount of virus is typically highest when the person is sickest. As the illness resolves, the amount of virus falls.”

In the press release, the CDC added that others “have encountered similar situations where test results have alternated back and forth between negative and positive.

“The cycle of the virologic infection on this particular patient is longer than what has been previously seen,” continued the statement.

That echoed concerns by health experts in recent weeks that a reliance on a 14-day incubation period for the virus, as has been common practice across much of the world, may be a mistake.

In fact, Abbott demanded Monday that repatriated Americans scheduled to leave quarantine at Joint Base San Antonio-Lackland not be allowed to exit the facility until federal officials can actually guarantee that they are not infected. Those at the base include evacuees from the notorious Diamond Princess cruise ship that saw an explosion in hundreds of cases in Japan.

“They must improve their protocols and they must be absolutely certain that before they allow anybody to be released from any location in San Antonio they can ensure the public that whoever they are releasing does not have coronavirus,” Abbott said.

Hours before Abbott stepped into the debate, San Antonio Mayor Ron Nirenberg called the CDC’s handling of the situation “unacceptable” and said he intends to hold the agency “accountable to providing complete transparency for the public.” A motion filed by city leaders seeking a temporary restraining order to prevent the release of cruise ship evacuees failed to win over a Texas judge on Monday, the Express-News reported.

“We are in dire need of additional resources and protocols immediately to include longer quarantine periods and the opening of appropriate facilities,” added Bexar County Judge Nelson Wolff.

Dr. Tedros Adhanom Ghebreyesus, director-general of the World Health Organization, said Monday that the rest of the world can learn from the virus’s patterns in South Korea, where the largest outbreak outside of China has infected more than 4,000 people.

“We are in uncharted territory,” he said. “We have never before seen a respiratory pathogen that is capable of community transmission, but which can also be contained with the right measures. If this was an influenza epidemic, we would have expected to see widespread community transmission across the globe by now, and efforts to slow it down or contain it would not be feasible.”

As of Monday morning, there were roughly 88,900 cases of novel 2019 coronavirus across the globe, of which 90 percent were still in China. More than 3,000 people have died.

Tedros said the five known clusters in Korea have been responsible for the majority of cases there, which indicates that “surveillance measures are working and that Korea’s epidemic can still be contained.”

That observation highlights a key problem in U.S., where surveillance testing—in which hundreds of people in possible hotspots are tested to proactively measure the virus’s presence—is not the norm. The CDC announced on Feb. 14 that it planned to implement surveillance testing in New York, Chicago, Los Angeles, San Francisco, and Seattle. But as of late last week, there was still no surveillance testing in the U.S., ProPublica reported. Epidemiologists in other countries have heavily relied upon this sort of testing in an effort to track the spread of the disease before—not after—large numbers of possible cases end up at hospitals.

“We’re weeks behind because we had this problem,” according to Scott Becker, chief executive officer of the Association of Public Health Laboratories, which represents 100 state and local public laboratories. Becker told ProPublica that “we’re usually up-front and center and ready.”

Vice President Mike Pence said over the weekend that the federal government had released 15,000 testing kits to labs in the U.S. in hopes of meeting the current demand in various states, adding that federal officials were working with a “commercial provider” to distribute 50,000 more soon.

Speaking alongside Pence, Alex Azar, Secretary of the Department of Health and Human Services, emphasized during a press conference in Washington late Monday that “the immediate risk to any individual American has been and does continue to be low” but that “the degree of risk has the potential to change quickly.”

Robert Redfield, director of CDC, added that health departments throughout the country “are aggressively evaluating to see if they can understand the linkage” of cases, as they pop up in Washington and elsewhere. “We have one of the finest public health programs in the world,” he said, later noting that the CDC will be able to activate surveillance testing around the country “in the near future.”

But even as federal officials from President Trump on down tried to calm financial markets and reassure the public, there were signs the government might be moving into a higher degree of alert. NBC News reported Monday the Federal Emergency Management Agency was planning for Trump to potentially make an emergency declaration over the outbreak, which would bring in extra funds and personnel.

One expert told the outlet this was “reassuring” and another deemed it a positive sign that “the president and the White House are finally aware of the gravity of the situation.”