Liberian President Ellen Johnson Sirleaf has said a man diagnosed with Ebola in Texas behaved irresponsibly when he travelled after being exposed to the virus, calling his actions "unpardonable".
Thomas Eric Duncan is the first person diagnosed with the deadly Ebola virus in the United States, after travelling from Liberia to Texas.
He was in contact with a known Ebola patient in Liberia, according to US media reports.
"The fact that he knew and he left the country is unpardonable," Ms Sirleaf told Canada's public broadcaster CBC.
She said although Liberia's airports are equipped with Ebola screening measures, Mr Duncan slipped past authorities, which Ms Sirleaf said could have put many at risk.
"[He] in a way put some Americans in a state of fear and put them at a state of risk, so I feel very saddened by that and very angry with him," she said.
The West African leader did not say what measures will be taken now, only that she would consult lawyers before deciding how to "deal with him" upon his return to Liberia.
Mr Duncan is being treated in a Texas hospital and four of his family members have been ordered to stay home, as authorities continue to scour the community for people he may have come into contact with.
The deadly Ebola virus has so far killed 3,338 people out of 7,178 infected, most of them in Liberia, Sierra Leone and Guinea.
Mr Duncan did not have a fever when he departed Liberia on 19 September but began to feel sick on 24 September after arriving in Texas.
He was initially sent home when he first sought medical care, leaving a four-day span when he was sick and contagious while in contact with others.
Once a patient begins to show symptoms like fever, vomiting and diarrhoea, they can infect others who come in close contact with their bodily fluids.
US health officials this evening said that after conversations with 100 people who might have been exposed to the patient, about 50 are now being observed daily for symptoms of the deadly virus.
Of the 50, about ten are considered at high risk, while the rest are considered at low risk, Dr David Lakey, commissioner of the Texas Department of State Health Services, said in a news conference.
Dr Beth Bell, director of the US Centers for Disease Control and Prevention's National Center for Emerging and Zoonotic Infectious Diseases, said putting people in observation does not imply the CDC has a "high level of concern" about most of these people.
The death toll for the outbreak has now risen to 3,431 out of 7,470 diagnosed cases.
US cameramen contracts Ebola
Meanwhile, a US freelance cameraman working for NBC News in Liberia has tested positive for Ebola.
He is the fifth US citizen and first journalist known to have contracted the virus in west Africa.
Ashoka Mukpo, 33, a cameraman and writer, will be flown back to the US for treatment, NBC said.
He has worked in Liberia for the past three years and has covered the recent Ebola outbreak for various US media outlets.
Four other NBC News team members who have shown no signs of infection will also return to the US to undergo a precautionary quarantine, the network said on its website.
Mr Mukpo began experiencing symptoms on Wednesday that included aches and fatigue, NBC said.
He was hired on Tuesday to serve as a second cameraman for NBC News chief medical editor and correspondent Dr Nancy Snyderman, who has been with three other network employees on assignment in Liberia's capital, Monrovia.
Immediately after beginning to feel sick and discovering he was running a slight fever, the cameraman quarantined himself and sought medical advice.
He then went to a Doctors Without Borders treatment centre to be tested for the virus, and the positive result came back less than 12 hours later, NBC said.
"We are doing everything we can to get him the best care possible," NBC News President Deborah Turness said in a note to network staff.
Ms Turness also said that as a precaution, Dr Snyderman and the rest of the NBC crew would be flown back to the US on a private charter plane and will place themselves under quarantine for 21 days, which she said is "at the most conservative end of the spectrum of medical guidance".
For now, she said, Dr Snyderman and her crew were being closely watched and had shown no symptoms of signs of the illness.
Dr Snyderman said in an interview yesterday that the cameraman's exposure to the potentially lethal virus is believed to have occurred before he began working for the network.
She said journalists in Liberia carry thermometers for regularly taking their temperatures and observe such precautions as avoiding handshakes and hugs, as well as washing their hands with diluted bleach and water and dipping their feet into bleach solution before entering hotels or other public places.
She said she wore a biohazard suit recently when visiting an Ebola ward, and was helped out of it afterwards by two nurses who "meticulously" removed the suit from her body.
"Obviously zero risk means never coming to Liberia," she said.
The four other US citizens who have been infected were doctors or relief workers who were sent back to the US for medical treatment.
Aid workers Dr Kent Brantly and Nancy Writebol contracted the disease at a relief agency in Monrovia in July.
Last month, Dr Rick Sacra tested positive after working in a Liberian hospital. They have all since been discharged from hospital.
A US doctor diagnosed with Ebola in Sierra Leone arrived at Emory University Hospital in Atlanta for treatment on 9 September and is still being treated.
