The suspected accomplice bought cell phone SIM cards -- memory chips that can be switched in cell phones -- for the attackers at several Indian locations, sources told CNN-IBN. Intelligence experts say the subscriber identity modules are used by terrorists to confuse pursuers.

Indian authorities said they believe the attackers were Pakistanis, specifically blaming Lashkar-e-Toiba, an Islamic militant group based in Pakistan. Pakistani authorities denied the attackers were from their country, blaming what they call "non-state" actors.

One analyst told CNN-IBN he thinks the operation was planned and carried out by militants from Bangladesh, Pakistan and India.

"They needed people on the ground who could guide them and provided the inside dope," said Shuja Nawaz, author of "Crossed Swords," an analysis of the role of Pakistan's military in the country's politics. "Otherwise, the Lashkar doesn't have the capacity to have cased the joints, to have made all these plans and get these people into the target area so effectively."

U.S. Secretary of State Condoleezza Rice, who met with Indian and Pakistani officials this week, stressed the need for Pakistan to hunt down Islamic extremists within its borders.

Meanwhile, Indian police handled a "security scare" of a possible airborne attack at New Delhi's major airport early Friday amid heightened security at the nation's airports, CNN-IBN reported.

Officials also are reviewing options on how to secure the country's coastline, which the Mumbai attackers used to entered the country.