A man arrested in Berkshire was the "manager" of a terror group whose members included some of the Madrid train bombers, a court has heard.
An extradition decision is expected on 14 June
Moutaz Almallah Dabas, 39, is accused of running a safe house in the Spanish capital where extreme Islamist recruits were trained before being sent abroad.
Details of the charges were read out at his extradition hearing at Bow Street Magistrates' Court, in London.
Mr Dabas was living in Slough with his family when he was arrested in March.
His family is said to include eight children.
Representing the Spanish authorities in court on Friday, John Hardy read out the European arrest warrant issued for Mr Dabas.
He said Mr Dabas, who was born in Damascus, Syria, but has Spanish nationality, was "effectively the manager" of a Muslim extremist group.
He told the court: "There were meetings at the house concerning the indoctrination and setting of a jihadist platform.
"[Mr Dabas] kept in his house texts authored by or distributed by Osama bin Laden and he stated his affinity to the jihadist thesis of Osama bin Laden and al-Qaeda."
Mr Hardy said telephone records showed Mr Dabas had been in contact with people involved in the March 2004 Madrid bombings, which killed 191 and injured 1,500, since 2002.
Among those believed to have attended meetings at his house was terror suspect Serhane Ben Abdelmajid Fakhet.
The Madrid bombing killed 191 people in March 2004
Fakhet was among seven prime suspects who blew themselves up when cornered by Spanish police on 3 April last year.
The warrant alleges Mr Dabas left Spain in 2002 but returned periodically during 2003, in particular for meetings with Fakhet.
Defence lawyer Mark Summers argued the arrest warrant was "defective".
Mr Dabas, wearing a white T-shirt, sat between three prison officers and said nothing during the short hearing.
He will re-appear via video link at Bow Street on 14 June, when an extradition decision is expected.