A suspected member of the terror cell that unleashed carnage in Spain last week admitted to a judge on Tuesday that the jihadists had planned to hit monuments in an even bigger attack.

Mohamed Houli Chemlal, 21, said he knew of the plans two months ago, as he, and three other suspects, appeared in court for the first time since twin attacks killed 15 people and wounded more than 100.

The four are the only surviving suspects from what was believed to be a 12-man terror cell that rammed a van into pedestrians on a tourist-packed boulevard in Barcelona on Thursday. Hours later, members of the group committed a similar attack in Cambrils further south.

After a full day hearing before the judge, Chemlal and another suspect, Driss Oukabir, 27, were remanded in custody and charged with terror related offences.

But the third man who owns the car used in the Cambrils attack, Mohamed Aallaa, was granted conditional release, with the judge saying evidence against him was weak.

The judge gave himself three more days to decide if the fourth suspect, Salh El Karib -- who manages a store that allows people to make calls abroad -- should be remanded or released from custody.

Chemlal, a Spaniard, told the judge the cell was planning "an attack on an even greater scale, targeting monuments" using bombs, a judicial source told AFP.

He had known of the plans for an attack "at least two months ago", he added.

- 'Imam wanted to blow himself up' -

Chemlal, dressed in hospital pyjamas and with his right hand bandaged, was brought in after a doctor said he was fit for interrogation, a court spokesman told AFP.

He was injured in an accidental explosion at the group's makeshift bomb factory on Wednesday evening. One of those killed in the blast was an imam, Abdelbaki Es Satty, who is thought to have radicalised him and other young suspects.

Chemlal only survived because he was out on the porch when the blast occurred.

He told the judge the imam had wanted to blow himself up. The judicial source said that among the four suspects, "two blamed the imam for the plot while another two denied knowing him".

Earlier, police had revealed that the suspected jihadists had been preparing bombs for "one or more attacks in Barcelona".

Details on their plans were outlined in the 14-page ruling issued following Tuesday's preliminary hearing.

source: AFP