Pakistan’s powerful intelligence services were heavily involved in preparations for the Mumbai terrorist attacks of November 2008, according to classified Indian government documents obtained by the Guardian.

A 109-page report into the interrogation of key suspect David Headley, a Pakistani-American militant arrested last year and detained in the US, makes detailed claims of ISI support for the bombings.

Under questioning, Headley described dozens of meetings between officers of the main Pakistani military intelligence service, the ISI, and senior militants from the Lashkar-e-Taiba (LeT) group responsible for the Mumbai attacks…

Headley, who undertook surveillance of the targets in Mumbai for the operation, claims that at least two of his missions were partly paid for by the ISI and that he regularly reported to the spy agency. However, the documents suggest that supervision of the militants by the ISI was often chaotic and that the most senior officers of the agency may have been unaware at least of the scale and ambition of the operation before it was launched.