Terrorists attacked two luxury hotels and several other sites in Mumbai last week, leaving at least 180 people dead.

ABC said U.S. intelligence agencies warned their Indian counterparts in mid-October. A second warning naming the Taj hotel was also issued. In mid-November, ABC said, Indian intelligence intercepted a phone call involving the Lashkar-e-Toiba terror group, a Kashmiri separatist group with ties to al-Qaida.

Ratan Tata, who chairs the company that owns the Taj, told CNN security temporarily was increased at the hotel but even if the measures had been retained, they would not have stopped the terrorists.

Intelligence agencies now are examining the SIM cards from phones that belonged to the terrorists, which could provide numerous leads in the investigation, ABC said.