A suspect arrested in Spain today has been linked to 9/11 ring leader Mohamed Atta

A terror suspect linked to 9/11 ringleader Mohamed Atta has been arrested in Spain.

The unnamed 43-year-old Egyptian was held in the town of Espinar around 40 miles north-west of Madrid.

Civil Guard officers are understood to have detained him during a dawn raid, on foot of a European arrest warrant for alleged membership of a terrorist organisation.

The suspect is said to have been investigated by German authorities over alleged links to a Hamburg-based terror cell smashed in April 2002, although local reports say he was subsequently released by authorities there.

He was expected to appear before a judge at an extradition hearing in Madrid late today.

According to US and German intelligence agencies, the Hamburg terror cell was formed by a group of radical Islamists based in the city that included students who ended up becoming key operatives in the 9/11 attacks.

Important members included Egyptian Mohamed Atta, who served as the hijacker-pilot of American Airlines Flight 11, crashing the plane into the North Tower of the World Trade Centre as part of the coordinated attacks.

A Spanish Ministry of Interior spokesman said the detention showed that 'once more, international cooperation in the fight against terrorism has proved key in neutralising potential threats to the security of Spain and its neighbours.'

Spain is understood to have swapped intelligence with Germany ahead of today's arrest.