Thirteen men have gone on trial in Belgium accused of membership of a militant group that has been linked to bombings in Madrid and Casablanca.
The trial is taking place amid high security
Prosecutors say the men - all Moroccans or Belgians of Moroccan descent - did not take part in bombings themselves, but supported others who did.
Defence lawyers say the only evidence against some of them is that they knew men charged with serious crimes.
The trial opened amid high security and was adjourned until 16 November.
The men are accused of belonging to the Moroccan Islamic Combatant Group (GICM), accused by the US of aiming to establish an Islamic state in Morocco and supporting al-Qaeda's jihad against the West.
Some are accused of providing false papers, safe houses and other logistical help to GICM militants.
Correspondents say this is one of the most important terror trials in Europe since the 11 September 2001 attacks in the United States.
A defendant shields his face in court
One of the suspects, Khalid Bouloudou, aged 30, is accused by prosecutors of supporting bombers who killed 191 people in Madrid in 2004, and 45 people in Casablanca in 2003.
Another, Youssef Belhadj, has been extradited to Spain on suspicion of appearing in a videotape admitting responsibility for the Madrid attacks.
Prosecutors say they have a phone-tap recording of a third defendant, Mourad Chabarou, talking by phone with the suspected architect of the Madrid attacks, Rabei Osman Sayed Ahmed, discussing "friends" who planted the bombs.
Mr Chabarou is accused of giving refuge in his house in Brussels to one of the Madrid bombing suspects, Mohammed Afalah.
Correspondents say some of the defendants are alleged to be close to the Netherlands-based Islamist group called Hofstad, one of whose members has received a life sentence for killing Dutch film-maker Theo van Gogh.
Of the 13 accused, 11 were present in court on Thursday.
Four, including Mr Bouloudou, were born and raised in Maaseik, a town of 24,000 on Belgium's border with the Netherlands.
Lawyers have questioned the strength of the case against their clients.
"Contacts, links, sympathy with people linked to a terrorist movement, is that really enough to consider that they have taken part in a terrorist organisation?" asked lawyer Filip Van Hende, quoted by AFP.
Another lawyer, Nathalie Gallant, told Reuters she would plead the innocence of Mostafa Louanani, who is accused of being one of the four leaders of the suspected cell.
She said the only evidence prosecutors had against him was that he knew men charged with more serious crimes.
A lawyer for three of the defendants requested permission to defend his clients in Dutch rather than French.
The request was rejected because it was made in Dutch rather than in French, the designated trial language. The lawyer said he would appeal.