A trial to determine the guilt of people accused in the commuter bombing attack that killed 191 persons in March 2004 in Spain is underway in the Spanish capital, Madrid.

Egyptian Rabei Osman became the first defendant in the case as he took the stand. However he said that he does not recognize any charges brought against him and refused to answer any questions, some of them asked by his own lawyer.

"Your honor, with all due respect, I do not acknowledge any accusations or charges. I am not going to answer any questions, including from my defense attorney", Osman said. The judge then cut him off as he tried to explain his reasons and asked prosecutor Olga Sanchez to start questioning the suspect. In an intercepted phone call after bombings, Osman had claimed that the attacks were masterminded by him. Osman was arrested in Italy.

Of the 29 people arrested, seven are accused of murder and belonging to a terrorist group. All the accused have pleaded not guilty to the charges brought against them. Eighteen of the suspects were seated in a bullet-proof chamber while 11 others, who were released on bail, sat in the main section of the courtroom.

The trial is expected to last for many months with over 100 experts and 600 witnesses likely to be called onto the witness stand, some of them survivors of the bombings that killed 191 people and injured over 1,700.

The seven accused of murders are expected to get 40 years of jail term, the maximum period allowed in Spain. The attacks were thought to have been planned by a local terrorist organization inspired by al-Qaeda.