A U.S. air marshal has been hospitalized after being attacked with a syringe at Lagos airport in Nigeria’s capital city, the FBI said Monday. While it is not known what was in the syringe, it is feared it may have contained a form of the Ebola virus.

After being flown back to the U.S., the official is currently under observation at a Houston area hospital where authorities are reportedly taking precautions against a potential spread of the disease, Associated Press, or AP, reported. Nigeria is one of the West African nations affected by the current outbreak of the Ebola virus.

"Out of an abundance of caution, the Centers for Disease Control and Prevention conducted an on-scene screening of the victim when United Flight 143 landed in Houston early Monday morning," the FBI reportedly said, in a statement. "The victim did not exhibit any signs of illness during the flight and was transported to a hospital upon landing for further testing. None of the testing conducted has indicated a danger to other passengers."

The attack on Sunday in Nigeria, which has also seen cases of Ebola, has fuelled fears that the syringe might have been carrying a type of the deadly virus. The latest and largest outbreak of Ebola till date has ravaged West Africa, killing more than 1,800 people and infecting more than 3,000 people. Treatments and vaccines aimed at controlling the virus' spread are still in the experimental stages, even as heath workers struggle to deal with patients infected with the contagious virus.

A travel ban on countries affected by the epidemic has only made the situation worse according to the United Nations, as airports around the world screen passengers for symptoms. The UN says it needs $600 million in funds to help battle the disease while U.S. President Barack Obama said the country needs to do more to help control West Africa's deadly Ebola outbreak to stop it from becoming a global crisis.