WASHINGTON (AP) — The Trump administration is alleging that a foreign disinformation campaign is underway aimed at spreading fear in the country amid the coronavirus pandemic, three U.S. officials said Monday.

On Sunday, federal officials began confronting what they said was a deliberate effort by a foreign entity to sow fears of a nationwide quarantine amid the virus outbreak. Agencies took coordinated action Sunday evening to deny that any such plans were put in place, as they tried to calm a nation already on edge by disruptions to daily life caused by the virus.

The three U.S. officials did not name the foreign entity they believe to be responsible. They spoke on the condition of anonymity to discuss the sensitive matter.

“Text message rumors of a national #quarantine are FAKE,” tweeted the National Security Council Sunday night. “There is no national lockdown.” The NSC encouraged Americans to follow official government guidance.

States and municipalities have banned large public gatherings, closed schools, bars and restaurants, and advised people to exercise so-called social distancing to slow the spread of the virus.

The Centers for Disease Control and Prevention on Sunday issued new guidance recommending against indoor gatherings larger than 50 people for the next eight weeks.

The nation’s top infectious disease expert, Dr. Anthony Fauci, said Sunday that Americans should aim to severely curtail leaving their homes, but did not indicate the government would order such a move. He was specifically questioned on whether he’d like to see a “national lockdown.”

“I think Americans should be prepared that they are going to have to hunker down significantly more than we as a country are doing,” said Fauci, a member of the White House task force on combating the spread of coronavirus. He heads the National Institute of Allergy and Infectious Diseases at the National Institutes of Health.

Rumors about the government’s response to the spreading virus have circulated online for weeks, prompting authorities in several states to urge residents to seek out trusted sources in government and news.

On Sunday, Massachusetts Gov. Charlie Baker said he’s been asked about the rumors by “senior leaders in business, healthcare, politics.”

“I’ve had community leaders and elected officials all text me or call me and say ‘I understand on Monday you’re basically going to order everybody to shelter in place for two weeks. The message has been exactly the same.”

“We have no plans to do that.”

He said it shows the need for residents to find trusted sources of news and information, such as legitimate news organizations or public health authorities.

“There’s so much information out there,” Baker said. “Some of which is legit, but a lot of it is wild speculation.”

Texts and posts suggesting Texas, Washington and New York states would be shutting down to prevent the spread of the coronavirus escalated with screenshots of text messages circulating online that claimed that within 48 to 72 hours Trump would place the U.S. under a two-week quarantine.

New York City officials last week debunked a claim passed around in text messages claiming the city’s Metro North trains, connecting commuters from the suburbs to the city, would be shut down and that other train service would be limited. Washington Gov. Jay Inslee also said claims that the state would soon be under quarantine were untrue.

Andy Carvin, a senior fellow at The Atlantic Council, a Washington based Think Tank, said the rumors circulating via text are the toughest to trace because they often percolate from private messaging platforms and texts, then are copy-and-pasted into public social media posts.

“There’s no way to know if these are organic or intentional, unfortunately, because the sentiment contained in them is so plausible that they could very easily be borne out of home-grown rumors,” he said.

For most people, the new coronavirus causes only mild or moderate symptoms, such as fever and cough. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia. The worldwide outbreak has sickened more than 156,000 people and left more than 5,800 dead. The death toll in the United States is more than 50, while infections neared 3,000 across 49 states and the District of Columbia.

Associated Press writers David Klepper in Providence, R.I. and Beatrice Dupuy in New York contributed to this report.