Two stowaways discovered aboard an Ethiopian Airlines flight after it landed in Dulles International Airport are being held on misdemeanor charges, according to immigration officials.

The two men were discovered Wednesday morning hiding in an overhead luggage compartment by a security guard during an inspection of the jet, after the other passengers had disembarked. Presumably, they had been hiding in the compartment for the duration of the flight from Ethiopia, a source told Fox News.

The stowaways, who are seeking asylum, were questioned by officials and placed in the custody of Immigration and Customs Enforcement pending an immigration hearing. It was not clear if the men were part of the Ethiopian Airlines cleaning crew that swept the jet before take off.

They are being held on charges of entering the United States without inspection.

They likely face deportation if they acted alone, but there could be more serious charges if investigators learn that others were involved or if the men were found to be testing security, Pat Reilly, a spokeswoman for U.S. Immigration and Customs Enforcement, said.

"We do not know if others are involved," she said. "If it turned out that they were smuggled into the country, there would be a criminal investigation."

The flight originated in Ethiopia, Reilly said, but she did not know if there were any stopovers where the men might have gotten on the plane.

Ethiopian Airlines' office in Alexandria, Va., was closed and not accepting messages by phone when contacted Thursday evening by The Associated Press.

If the men got on the plane in Ethiopia, U.S. investigators can work with security officials there to determine how the breach happened, Reilly said.

FOX News reporter Catherine Herridge and the Associated Press contributed to this report.