A nurse who cared for Ebola patients in Sierra Leone is fighting the US state of Maine over its right to quarantine her against her will.
In a test case for returning US health workers, Kaci Hickox has vowed to leave her home on Thursday if the state does not lift the restrictions.
President Barack Obama has been sharply critical of isolation being forced on people he says are “American heroes”.
Almost 5,000 people have died from the Ebola virus, mostly in West Africa.
On Thursday, US ambassador to the United Nations Samantha Power is expected to call for a stronger international response when she meets EU officials in Brussels.
She has been visiting the countries most affected – Guinea, Sierra Leone and Liberia – to show US support, as well as Ghana, where the United Nations Mission for Ebola Emergency Response is based.
The infection last week of a doctor in New York who had returned from Guinea has sparked a debate in the US over isolation policies for people coming back from West Africa.
Dr Craig Spencer had travelled on the subway and been bowling the night before he developed a fever, which is the point when people become contagious.
The governors of New York and New Jersey introduced mandatory quarantines as a result, and Ms Hickox was outraged to be put in a tent in Newark on returning from Sierra Leone last Friday.
Officials said she had a temperature – which she denies – but she was released from Newark on Monday and flown back to Maine to be monitored at her boyfriend’s house in Fort Kent.
“I am not going to sit around and be bullied around by politicians and be forced to stay in my home when I am not a risk to the American public,” said Ms Hickox, who has tested negative for Ebola twice and has no symptoms.
She appeared briefly outside the house on Wednesday night to speak to reporters and express her continued frustration.
“I’m not willing to stand here and let my civil rights be violated when it’s not science-based,'” she said.
But Maine Governor Paul LePage has said he would seek legal authority to keep her isolated at home until 10 November.
“While we certainly respect the rights of one individual, we must be vigilant in protecting 1.3 million Mainers, as well as anyone who visits our great state,” he said in a statement.
California became the latest US state to announce tough rules for people returning from the Ebola-hit region.
These states are in defiance of the updated federal guidelines issued on Monday that call for active monitoring but not quarantine.
Twice this week, President Obama has condemned quarantine as a policy based on fear, not science, while praising the work of US aid workers.
“We need to call them what they are, which is American heroes,” he said.
“They deserve our gratitude, and they deserve to be treated with dignity and with respect.”
But he has faced questions why the Pentagon is imposing a 21-day isolation on returning military personnel, despite them not coming into contact with Ebola patients while working to build clinics in West Africa.