Nigerian prosecutors on Monday widened charges against three Lebanese nationals accused of links to Hezbollah as their trial began with access to the courtroom restricted and the identities of witnesses concealed.
Mustapha Fawaz, 49, Abdallah Thahini, 48, and Talal Ahmad Roda, 51, have been accused of having ties to the powerful Lebanese Shiite Muslim group Hezbollah and plotting attacks against Western and Israeli targets in Nigeria.
Prosecutors brought fresh charges related to money-laundering and illegal importation of goods among crimes.
These came in addition to the terrorism-related offences filed last month after a massive supply of weapons was found at a business in the capital Abuja and a private home in the northern city of Kano.
"We want to be sure that all elements of every offence disclosed by the investigation is properly before the court," prosecutor Simon Egede said.
Judge Adeniyi Adetokunbo Ademola agreed to a prosecution request to restrict access to the hearings, with only the defendants, their legal teams, journalists and two relatives per each accused allowed in.
He said the identities of the prosecution witnesses would not be revealed for security reasons.
Agents of the Department of State Services (DSS), Nigeria's main intelligence branch, wore face masks when they testified Monday.
The defendants have pleaded not guilty to all charges but prosecutors say they have admitted membership in Hezbollah, which is not a crime in Nigeria.
The trio are believed to own a supermarket and an amusement park in Abuja, but the businesses have been shuttered since the arrests.
A fourth suspect is said to be on the run.
Nigeria is grappling with a deadly Islamist insurgency waged by Boko Haram, but there has been no suggestion of any ties between the Lebanese accused and the Nigerian extremist group.
Nigeria, Africa's most populous country, is home to a sizeable Lebanese population, including in the mainly Muslim north.