A brother of one of the men blamed for the Omagh bomb atrocity paid €10,000 (£8,600) to arm the Real IRA with guns and explosives from Lithuania, a court heard today.
Michael Campbell was arrested in an undercover operation in the Baltic state after handing over cash to buy a sniper rifle, detonators and timers, the court in Vilnius city was told.
New details of the international sting operation emerged today as the trial was adjourned until October.
Lithuanian prosecutors alleged Campbell attempted to negotiate a deal for guns, ammunition and bomb-making materials for the dissident republican group.
He faces up to 20 years in prison if found guilty.
The defendant is the brother of Liam Campbell, who was successfully sued by the relatives of the Omagh victims for the 1998 bomb attack which killed 29 people.
The pair are from the Upper Faughart area near Dundalk, Co Louth, in the Irish Republic, close to the border with Northern Ireland.
Michael Campbell is charged with supporting a terrorist group by attempting to smuggle firearms, ammunition, and explosive devices from Lithuania to Ireland.
Irmantas Mikelionis, deputy chief prosecutor of Vilnius, said Campbell was arrested in January 2008 following the operation involving the British, Irish and Lithuanian intelligence agencies.
It is alleged the 36-year-old paid undercover Lithuanian agents 10,000 euro for the weapons including a sniper rifle, detonators, timers and about 10kg (22lb) of high explosives, in a garage in the industrial zone of Vilnius.
It is also claimed he illegally carried and fired from a rifle, an AK-74 and pistols and examined a sniper rifle, mechanic timers and high explosive trotyl.
It is maintained agents were asked how much of the lethal substance would be needed to blow up a police car or government fire-proof car, and if they would train Real IRA members on how to use the weapons.
Campbell, who has been in custody in Lithuania since his arrest, has not yet entered a plea.
Meanwhile, authorities in Vilnius have begun extradition proceedings against three men - Liam Campbell, Seamus McGreevy and Brendan McGuigan - who are wanted for questioning in relation to the alleged arms smuggling operation.
"The General Prosecutor of Lithuania has issued European arrest warrants, and we are seeking that they would be surrendered," added Mr Mikelionis.
Liam Campbell is in custody in Northern Ireland, while the case against McGuigan, 29, of Omeath, Co Louth and McGreevy, 56, of Gormanstown, Co Meath, will be heard in Dublin's High Court in November.
All charges have been dropped against a woman who was detained with Michael Campbell.
The Real IRA splinter group was responsible for the no-warning Omagh bomb in 1998 in which 29 people were murdered, including a woman pregnant with twins.
In a landmark multi-million civil lawsuit, Liam Campbell and three others were successfully sued by the relatives of the Omagh victims earlier this year.
The Real IRA was also found liable for the attack.
In June, Mr Justice Morgan awarded more than £1.6 million (1.84 million euro) in damages to 12 named relatives who took the action.
The judge said he was satisfied Liam Campbell was a member of the army council of the Real IRA at the time of the bombing.