Addressing the Parliament on Thursday, Prime Minister Manmohan Singh offered apology for the Mumbai attack.

Ten SIM cards were bought a month back from three different locations in Kolkata and sent to Pakistan via Bangladesh out of which three were used by Lashker-e-Taiba terrorists in the audacious Mumbai attack, investigations have revealed.

United States intelligence agencies had warned India "twice" about a potential maritime attack on Mumbai at least a month before audacious terror strikes that has left about 200 people dead and scores injured, media reports said.

Nationalist Congress Party chief and Union Agriculture Minister Sharad Pawar has accepted that security establishments in the country were totally unprepared to handle an attack like the one in Mumbai.

The Taj Mahal Palace and Trident Hotel in Mumbai had been warned of a possible terrorist attack and had temporarily beefed up security, but nothing could have stopped the gunmen, Ratan Tata, chairman of the Tata Group that owns the hotel, said in an interview to be broadcast on Sunday.