Women leaving Lagos airport wearing face masks and gloves. Ebola has spread to Nigeria. Photograph: Pius Utomi Ekpei/AFP/Getty Images
A US air marshal was attacked with a syringe at Lagos airport in Nigeria and has been taken to a US hospital, the FBI said on Monday.
It was not known what was in the syringe when its contents were injected into the on-duty marshal, whose name has not been given and is in hospital in Houston.
The incident on Sunday raised fears the syringe could have carried some form of the Ebola virus because Nigeria is one of the west African countries where the epidemic has spread.
The FBI said authorities were taking every precaution but that initial signs were that the victim was not a danger to others and was not showing any symptoms.
"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 statement said.
"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."
US federal air marshal in quarantine after he was stabbed in the arm with a syringe and 'injected with foreign substance' at Nigerian airport
A U.S. federal air marshal was injected in the back of the arm with an unknown substance at Lagos airport
The assailant has not been located and a motive has not been established
The air marshal was quarantined and screened for Ebola on-scene
He was allowed to board the United Airlines flight he was booked on for Houston
He is having further tests in the United States
The syringe was also transported to the U.S. for testing
A federal air marshall has been quarantined in Houston after he was injected with a syringe full of an unknown substance inside Lagos airport in Nigeria.
The man reported the attack, which occurred in an unsecured, public area of the terminal, and the FBI and the Centers for Disease Control and Prevention (CDC) are investigating.
The man was able to board United Flight 143 and landed in Houston early Monday morning where he was taken for medical testing.
Mysterious attack: A U.S. federal air marshal was injected with an unknown substance by an unknown assailant at the Murtala Muhammed International Airport in Lagos
According to ABC News, the man was standing with a group of other air marshals when an assailant injected an unknown substance into the back of one of his arms.
The assailant ran off and could not be located after the attack.
The federal air marshall, who has not been named, was immediately quarantined and screened on-scene for Ebola virus, 'out of an abundance of caution,' according to the FBI.
The federal air marshall did not immediately display any signs of ill health and was allowed to board the flight he was scheduled to work on.
No motive: The attack happened in a public part of the airport and the attacker fled and has not been captured
The syringe was recovered and also taken aboard the flight to be tested in the United States.
U.S. federal air marshals travel incognito, so the assailant would not have been able to identify the victim as a U.S. federal law enforcement agent from his appearance.
'While there is no immediate intelligence to confirm this was a targeted attack, this is our reminder that international cowards will attempt to take sneaky lethal shots at our honorable men and women abroad,' Jon Adler, the national president of the Federal Law Enforcement Officers Association, said, reports ABC News.