Vilnius  - An Irishman accused of attempting to buy arms for a paramilitary group while he was in Lithuania had his appeal against being kept in jail rejected Thursday.

The Court of Appeal in the Lithuanian capital upheld a decision by Vilnius Regional Court that 36-year-old Michael Campbell should be kept in custody until the case is heard in October.

Campbell did not appear in person and has already been detained in the Baltic state for more than 18 months.

He is accused of attempting to buy arms for the dissident paramilitary group known as the Real IRA. He was arrested in Lithuania in January 2008 after a sting operation involving British, Irish and Lithuanian security services.

He denies attempting to buy arms and his legal representatives say their client was attempting to buy contraband cigarettes rather than weapons when he handed over a large amount of cash to undercover agents posing as smugglers.

Some sessions of the trial are due to be held behind closed doors to protect the identities of individuals employed by state security organizations, including agents of Britain's MI5 secret service.

The Lithuanian State Security Department (VSD) has said at least one witness could be on a Real IRA hit list.

The Real IRA split from the better-known Irish Republican Army (IRA) in 1997. While the IRA has laid down its arms and joined in the Northern Ireland peace protest, the smaller Real IRA favours the use of military methods to try to end British rule in Northern Ireland.

In the 1990s, many East European capitals became destinations for paramilitary groups around the globe looking to buy weapons.

Large stocks of Soviet-era arms, plus officials open to corruption, created a lucrative marketplace that was quickly taken over by criminal gangs.

Lithuania joined the European Union in 2004.(dpa)