A Spanish court found 21 people guilty of involvement in the 2004 Madrid train bombings but cleared three men of masterminding Europe's deadliest Islamist attack, which killed 191 people.

Victims were shocked by the sentences, which in many cases were much lower than the state attorney had requested and left them without any clearer idea of who dreamed up the attack that ripped apart four commuter trains like tin cans.

Judge Javier Gomez Bermudez sentenced three men -- two Moroccans and a Spaniard who provided the bombers with explosives -- to as many as 42,924 years in prison but nobody else got more than 23 years and seven people were acquitted.

Under Spanish law nobody can serve more than 40 years in jail.

Isabel Presa, who lost her youngest son in one of the explosions, shook as she told journalists of her disgust at what she regarded as lenient sentences.

"I'm not a judge or a lawyer but this is shameful, outrageous," she said before breaking down in tears.

The biggest surprise was that two men originally accused of planning the attack were convicted only of belonging to a terrorist group, not of the Madrid killings.

A third suspected mastermind Rabei Osman Sayed Ahmed or "Mohamed the Egyptian" was cleared of all charges. His lawyer in Italy, where he is in jail for belonging to a terrorist group, said he fell on his knees in prayer when he heard the ruling.

"We're very surprised by the acquittal," said Jose Maria de Pablos, spokesman for a victims' association. "If it wasn't them, we have to find out who it was. Somebody gave the order."

Another victims' group said they planned to appeal the ruling. Lawyers have said some of the accused could also appeal.

THREE MAIN CONVICTS

Ten bombs packed into sports bags and detonated by mobile phones tore through the trains on March 11, 2004, leaving the tracks strewn with bodies and injuring more than 1,800 people.

Three weeks later, seven men including two suspected ringleaders of the train bombings blew themselves up in a suburban apartment after police closed in on them. The explosives were the same as were used in the March 11 attack.

They may have taken with them the main evidence of who was behind the attack, which the magistrate who investigated the bombings said was inspired by, but not directed by, al Qaeda.

The court laid most of the charges at the feet of the three men sentenced to thousands of years in prison.

Jamal Zougam was found guilty of belonging to a jihadist terrorist cell and convicted of terrorist murder. He was seen by three witnesses on the trains that blew up.

Fellow Moroccan Othman el Gnaoui was convicted of the same charges and found guilty of helping to get explosives to a house near Madrid where the bombs were prepared. Spaniard Jose Emilio Suarez Trashorras was found guilty of providing the explosives in the knowledge they could be used for a terrorist attack.

At the sentences were handed out, the three men sat silently behind bullet-proof glass staring at the judge or the floor.

As he summed up the trial, Judge Gomez Bermudez again said there was no proof Basque separatist rebels ETA had anything to do with the train bombs, despite some media and victims' support groups still insisting there must be some link to them.

The conservative government in power in March 2004 at first pinned the attack on ETA but as more evidence piled up to show it was the work of an Islamist cell, Spain turned against its leaders and voted them out of power three days later.