The claim is based on scouting by a Chicago man recently charged with being a long-time clandestine operative of the group, according to current and former US, Indian and European counterterrorism officials.
FBI and Justice Department officials spent last week in India and Pakistan as part of an urgent effort to head off such an attack, sharing a wealth of information from their investigation into the activities of David Coleman Headley, the officials said.
The new plots, believed to be in the works for months, are most likely against “soft” civilian targets such as hotels or synagogues frequented by Americans, Israelis and other Westerners, the officials said.
But India's National Defense College and other government sites have also been scouted as targets, according to officials and FBI affidavits recently unsealed in Chicago.
The Justice Department last week filed terrorism charges against a third former Pakistani military officer in the Denmark plot.
Those accusations are sure to exacerbate tensions in the region, current and former US and allied officials said. Washington and India have long accused the Pakistani military of maintaining close ties to Lashkar and other militant groups and using them for attacks on India.
Pakistan has long denied those accusations and demanded proof.