Post 26/11, a section of the Congress leadership was seen playing religious politics after one of its leaders, A. R. Antulay, said that Hindutva forces may have been involved in the Mumbai terror attacks, according to a confidential memo by the then U.S. Ambassador to India, David Mulford, released by WikiLeaks.

“The Congress party, after first distancing itself from the comments (of Antulay, the then Minority Affairs Minister), two days later issued a contradictory statement which implicitly endorsed the conspiracy. During this time, Mr. Antulay’s completely unsubstantiated claims gained support in ... Indian—Muslim community,” Mr. Mulford wrote in his secret cable to the State Department on December 23, 2008.

“Hoping to foster that support for upcoming national elections, the Congress Party cynically pulled back from its original dismissal and lent credence to the conspiracy,” Mr. Mulford wrote.

Regardless of Home Minister P. Chidambaram’s dismissal of Mr. Antulay’s comments, the Indian—Muslim community “will continue to believe they are unfairly targeted by law enforcement and that those who investigate the truth are silenced,” he said in the cable.

“The entire episode demonstrates that the Congress Party will readily stoop to the old caste/religious—based politics if it feels it is in its interest,” Mr. Mulford alleged, according to the cable posted by WikiLeaks on its website on Friday.

The United States has neither confirmed or denied the authenticity of these cables, but said that some 250,000 papers have been stolen from its system and demanded that WikiLeaks — the whistle blower website — return them back to the State Department.

According to WikiLeaks, there are some 1,300 cables from the U.S. embassy in New Delhi. However, only half a dozen of them have been posted by it on its website.

Mr. Mulford said while the killing of three high-level law enforcement officers during the Mumbai attacks, including ATS chief Hemant Karkare, “is a remarkable coincidence, the Congress Party’s initial reaction to Antulay’s outrageous comments was correct.”

“But as support seemed to swell among Muslims for Antulay’s unsubstantiated claims, crass political opportunism swayed the thinking of some Congress Party leaders,” he wrote.

“What’s more, the (Congress) party made the cynical political calculation to lend credence to the conspiracy even after its recent emboldening state elections victories. The party chose to pander to Muslims’ fears, providing impetus for those in the Muslim community who will continue to play up the conspiracy theory,” Mr. Mulford wrote in his cable.

While “cooler heads” eventually prevailed within the Congress leadership, the idea that the party would entertain “such outlandish claims proved once again that many party leaders are still wedded to the old identity politics,” he said.

The 79-year-old Antulay “was probably bewildered to find that his remarks, similar in vein to what he would have routinely made in the past to attack the BJP, created such a furore this time,” Mr. Mulford said.

The cable noted that Mr. Antulay “sparked a political controversy on December 17 with comments insinuating that the killing of Maharashtra Anti-Terror Squad (ATS) Chief Hemant Karkare by the Mumbai terrorists was somehow linked to Karkare’s investigation of (Malegaon) bombings in which radical Hindus are suspected.”