Madrid - Spain's National Court on Tuesday acquitted 10 suspected Islamists because of irregularities in the police investigation, judicial sources said.

The court concluded that a cell formed by a total 14 accused, who were detained in 2005 in the Barcelona region, had recruited fighters to travel to Iraq for attacks.

But because the e-mail accounts of the 10 had been opened without the corresponding judicial permits, the court found it had no alternative but to acquit them.

The court said the prosecutor had not tabled other relevant evidence against the 10 accused.

The court did, however, find valid evidence against four of the accused, who were handed from 2 to 9 years in prison.

The Mujahideen recruited by the convicts included some suspects in the Madrid train bombings, who are believed to have travelled to Iraq after the attack.

In 2007, 21 people were sentenced for the bombings which killed 191 people in the Spanish capital in 2004.