FORT KENT — Gov. Paul LePage says negotiations have broken down with Kaci Hickox, the nurse who treated Ebola patients in West Africa, and that the state is prepared to use “the full extent of his authority allowable by law” to protect the public health.

The governor issued that statement Thursday afternoon, four hours after Hickox returned from an hourlong bike ride with her boyfriend, in defiance of the state’s insistence that she be quarantined in her house for 21 days.

The governor’s office put out a statement that read, in part: “Maine statutes provide robust authority to the State to use legal measures to address threats to public health.”

He was not specific, however, about what steps the state was taking and said such specifics could not be discussed because of confidentiality provisions in the law.

The release indicated that the governor’s office and the state attorney general had been negotiating with Hickox and her attorneys, and that he would be amenable to following guidelines like those recommended by the federal Centers for Disease Control, which call for monitoring and avoidance of crowds and public places, but do not require that a person be isolated at home.

The state’s position on quarantine appears to have changed significantly and would allow Hickox to leave her house as long as she avoids contact with the public.

Monday, the day Hickox was released from a quarantine in New Jersey, Maine health officials announced they had more stringent protocols than those called for by the federal CDC.

“Maine will take further measures, out of an abundance of caution, to ensure public safety. … We will work collaboratively with the affected individual to establish quarantine of the individual in his or her home for 21 days after the last possible exposure to Ebola,” the Department of Health and Human Services said. Later, the state called for “an in-home quarantine protocol to ensure there is no direct contact with other Mainers until the period for potential infection has passed.”

The Maine CDC “in-home quarantine” guidelines now reflect the federal Centers for Disease Control recommendations for someone who is at “some risk” but shows no symptoms. The federal CDC does not call it quarantine.

The federal guidelines, and now the state’s, call for direct active monitoring of a person who has treated Ebola patients, which means in-person visits to check on the person’s condition. A Maine CDC epidemiologist, someone who monitors and investigates disease risk in populations, visited Hickox’s home again Thursday and was inside for just a couple of minutes, presumably as part of the direct active monitoring.

The guidelines also can include – and in the Maine do include – restrictions on the use of long-distance transportation like buses or airplanes, exclusion from public places like shopping centers and movie theaters and staying away from work.

The person can go outside as long as he or she remains at least 3 feet from members of the public.

“These guidelines would allow an individual in the “some risk” category to go for walks, runs or ride their bicycle, but would prevent such a person from going into public places or coming within three feet of other people in non-congregate gatherings,” the governor’s statement said.

The guidelines appear to be tailored specifically for this case.

“The Governor remains willing to enter into such an agreement, on a case-by-case basis, with traveling healthcare workers who meet this definition,” Thursday’s news release says.

It is not clear whether the restrictions would apply to healthcare workers who treat people with Ebola in this country.

The statement did not address a question posed to LePage’s press secretary about whether the governor was willing to abandon the quarantine in favor of a blood test, as was reported by ABC News.

Neither Hickox nor her lawyers have commented on the new protocols, though Hickox has said earlier that she believes she should be able to engage in activities like going to the grocery store.

“You know more than we do,” Hickox told a Portland Press Herald reporter at the door of her home earlier Thursday afternoon. “I’ve seen nothing in writing.”

When asked whether she would be amenable to taking a blood test to establish that she does not have the Ebola virus, Hickox said, “We’ll decide that later.”

Hickox had blood tests, which were negative for Ebola, while quarantined in New Jersey last weekend.

LePage had been softening his stance on the case. He told Channel 13 in an interview “I just want to protect Maine from that. That’s all. And if the court says not to worry, hey, don’t worry. I’m not going to go next to her.”

Maine Center for Disease Control & Prevention Director Dr. Sheila Pinette said Tuesday that Hickox “may have been tested too early” in New Jersey, and that there’s a chance that early tests would produce a false negative for Ebola. Some early tests for Ebola look for antibodies to the virus, which may not be detectable early in the 21-day incubation period. She said the only way to be sure Hickox does not have the virus is to wait the full 21 days.

Hickox returned to the U.S. Friday after treating Ebola patients in Sierra Leone for the aid organization Doctors Without Borders.

Mary Mayhew, commissioner for the department of Health and Human Services, said Wednesday that the state will go to court to enforce the quarantine on any health-care worker who has returned from treating infected patients in West Africa.

A spokesman for Attorney General Janet Mills would not say whether the state has yet gone to court to seek a mandated quarantine, noting that such orders are confidential.

The confrontation pits the recommendations of the nation’s health-care establishment, including the federal Centers for Disease Control, against a handful of governors who have sought more stringent restrictions on health-care workers returning from Ebola-affected countries.

President Barack Obama, in a press conference Wednesday, said that subjecting returning health-care workers to lengthy quarantines is motivated by fear, not science, and will be counterproductive because it will dissuade people from joining the fight against the disease in West Africa.

Asked why Maine is not following the federal guidelines, Mayhew said Wednesday that there is no leadership on the issue coming from Washington.

The confrontation has escalated into a civil rights issue, with the state seeking to restrict Hickox’s movements, citing concern for the broader community.

The American Civil Liberties Union of Maine issued a statement Thursday morning saying Hickox’s situation is not one in which public safety would justify limiting her civil liberties.

“In times like this, it is of utmost importance that the government remain transparent and even-handed and avoid overreaction,” Executive Director Alison Beyea said. “Extreme measures like mandatory quarantines and police intervention raise serious concerns about government overreach, not to mention frighten the public.”

Hickox said Thursday’s bicycle ride was unplanned and not coordinated with her lawyers.

“I said to Ted this morning, ‘Let’s go for a bike ride,’ ” Hickox told reporters stationed outside her house. “It was a nice bike ride.”

It’s unclear how the state plans to respond, but state troopers and local police followed the pair as they rode. They made no move to stop or detain her.

State Police reiterated that they have been assigned to watch the house at the request of the governor’s office, to monitor the nurse’s movements “for both her protection and the health of the community.”

Hickox and Wilbur pulled out onto Violette Settlement Road, followed by about 40 reporters and a handful of police. They rode through the neighborhood and onto a trail. The couple returned from their bike ride just before 10 a.m. to dozens of cameras positioned outside. Cars belonging to members of the media lined the road in each direction.

Hickox thanked the media for their presence before going inside.

Hickox, who treated Ebola patients in West Africa, vowed Wednesday to wage a legal battle against Maine’s intention to enforce a 21-day quarantine with a court order.

Hickox and Wilbur addressed the media outside his house here Wednesday night, as local and state police watched from across the street.

“We have been in negotiations all day with the state of Maine and tried to resolve this amicably, but they are not allowing me to leave my house and interact with the public even though I am completely healthy and symptom-free,” Hickox said Wednesday. “I am frustrated by this fact, and I have been told that it is the attorney general’s intention to file legal action against me. And if this does occur, I will challenge the legal actions.”

Stephen Hyman, Hickox’s attorney, said Thursday morning that he had heard Hickox and Wilbur had left the house, and reiterated that she has every right to leave and the state has no legal authority to force her to stay in her house.

During a news conference on Wednesday, Mayhew said the state plans to go to court to enforce the quarantine it has established for any health worker who was treating Ebola patients in West Africa. It’s not clear when a court order would be sought.

Mayhew urged health workers returning from West Africa to abide by state restrictions, which exceed federal guidelines, that are intended to prevent the spread of the disease. If they don’t comply, the state will try to get a judge to order it.

The ultimatum was clearly directed at Hickox.

Hickox said she had negotiated with Maine officials in an attempt to “meet them halfway” by making some concessions, such as avoiding public transportation and staying in the Fort Kent area, but the state rejected her terms.

Mayhew said that if a health care worker mingles with the public, then develops symptoms, state health workers would have to track down everyone she had contact with. She said a similar scenario was playing out in New York City, where Dr. Craig Spencer developed symptoms and was diagnosed with Ebola a few days after returning from Guinea, where the disease is rampant and he treated patients for Doctors Without Borders.

The editorial board of the New England Journal of Medicine cited the same case to demonstrate that health care professionals can be trusted to report when they become symptomatic and that there is not suggestion that anyone else became infected by contact with him.

Hickox, who returned to the United States on Friday, was visited by a health official Wednesday afternoon. The woman was met outside the house by Wilbur, who had said he was waiting for a representative of the “health department.”

The woman was escorted by a Maine State Police trooper who had been stationed at the house since early Wednesday morning. She entered by a side door, remained inside for two or three minutes, then left.

The woman was not wearing any protective clothing when she entered and left the house. She did not take questions from the media or identify herself.

Under the state’s proposed quarantine rules, Hickox is allowed to have visitors who are not wearing personal protective equipment.

Staff writer Scott Dolan contributed to this report.

This story will be updated.