Army officials cited initial screening results that showed the soldier was not infected with Ebola.
"At this point, there is no indication of the Ebola virus disease, but medical tests are under way to ensure there is no threat to the community," the officials said.
They were echoed by Killeen police spokeswoman Carol Smith, who also warned against jumping to conclusions.
"We are not saying Ebola at all. It's just that because of the circumstances from West Africa, we are erring on the side of caution," she said.
The soldier returned to Fort Hood after having served in Liberia since last October, when a Fort Hood brigade was deployed in Liberia to support "Operation United Assistance," which is aimed to help control the Ebola outbreak in the West African country.
The soldier was reportedly granted emergency leave from the 21-day Ebola quarantine for family reasons.
He was self-monitoring for Ebola symptoms twice daily and reporting his status to medical officials.
Meanwhile, the US Centers for Disease Control and Prevention has reported four cases of Ebola which were diagnosed in the United States.
They included Liberian national Thomas Eric Duncan, who infected two nurses, Nina Pham and Amber Vinson, after he was treated at Texas Presbyterian Hospital in Dallas.
The fourth case was Dr. Craig Spencer, who was diagnosed in New York City after returning from Guinea in October 2014.
Thomas Eric Duncan remains the only patient to have died of the Ebola virus in the United States.
