Eurabia Alert. "Catalunya es la base europea de una filial paquistaní de Al Qaeda," by Antonio Baquero and Jordi Curachan for [1] El Periódico (my translation):

Spain, and especially Catalonia, has been converted into the principal base of Jaish-e-Mohammed (the Army of Mohammed) in continental Europe, a Pakistani terrorist group tied to the central command of Al Qaeda and implicated in the July 7, 2005 attacks in London.

Sources from the Pakistani security forces alerted this paper that JEM "has recruited Pakistanis residing in Spain, and have sent them to Pakistan, where they have put them at the disposal of the networks of Al Qaeda in the tribal zones," in an itinerary tracing the route which Shehzad Tanweer and Mohammad Sidique Khan, the authors of July 7, took in November, 2004.

These sources emphasized the "collaboration" between the Spanish and Pakistani spy services, which allowed them to follow very closely the travels between Spain and Pakistan by various individuals.

The same sources said that, in Spain, JEM uses "mosques to recruit and mobilize volunteers for jihad, as they do in Great Britain as well." The Pakistani officials indicated that JEM uses Spain, and especially the Catalonian territory, as a logistical base. "In Catalonia, its members raise funds and send stolen European passports to Pakistan," they advised.

[...]

JEM is not the only Pakistani group that has penetrated Spanish territory. The sources from the Pakistani security forces indicate that another group, Lashkar e Toiba (LET, the Army of the Pure), a movement responsible for numerous attacks in India, has succeeded in implanting itself in Spain, where it is essentially dedicated to raising funds."