A lawsuit filed in a New York court by relatives of two Jewish victims of the Mumbai attacks was "against the alleged perpetrators and masterminds, i.e. Hafiz Saeed, Zakiur Rehman Lakhvi and others", sources in the ISI were quoted as saying by The News daily.
The sources claimed the Inter Services Intelligence agency had no role in the attacks and the inclusion of the names of former ISI chiefs Nadeem Taj and Ahmed Shuja Pasha was "only done to smear the agency and get it declared a terrorist organisation".
"There is no rocket science involved in the issue. The ISI and its (directors general) have had no role whatsoever in the Mumbai incident as regularly reported by the Indian media," a source was quoted as saying.
The sources in ISI appreciated the role of the US in "sorting out the issue" related to its former chiefs.
"We are glad that the US government prudently supported the claim of the Pakistan government. It is a US decision that we admire and appreciate," a source said.
There is "no need to fabricate cock and bull stories on the subject", the sources claimed.
The US State Department recently informed a New York court hearing the lawsuit that the ISI and two of its former chiefs "enjoy immunity" and cannot be tried for the Mumbai attacks.
"Upon consideration of this matter, and after a full review of the pleadings, the Department of State has determined that defendants Ahmed Shuja Pasha and Nadeem Taj are immune from suit in this case," an official letter said.
The Pakistan government has acknowledged that the conspiracy behind the Mumbai attacks was hatched in the country.
It also acknowledged that Ajmal Kasab, the lone surviving terrorist involved in the attacks, was a Pakistani citizen.
Kasab was hanged in a Pune jail last month.
Pakistani authorities have arrested seven suspects, including Lashkar-e-Taiba commander Zakiur Rehman Lakhvi for planning and executing the attacks but their trial has stalled for over a year due to various reasons.
Despite considerable information gathered by Indian and US investigators, the Pakistani military and the ISI has claimed that none of its personnel were involved in the attacks that killed 166 people in November 2008.