Home Minister Shivraj Patil said he took "moral responsibility" for the assault by heavily-armed militants which left nearly 200 people dead and transformed parts of Mumbai into a war zone for three days.
With tensions escalating in South Asia, Pakistan President Asif Ali Zardari urged India not to "over-react" after Indian and US officials suggested the gunmen could have been members of Lashkar-e-Taiba.
Lashkar, which is fighting Indian control of the disputed Kashmir region, was behind a deadly 2001 assault on the Indian parliament that pushed New Delhi and Islamabad to the brink of war.
Indian media reported that the only surviving militant had identified all the Mumbai attackers as Pakistanis who had been trained by Lashkar.
Ajmal Amir Kamal, 21, who was caught on a CCTV camera wearing a T-shirt with a "Versace" logo, was being interrogated in a safe house in Mumbai, reports said.
US counter-terrorism officials told AFP that evidence was emerging that Lashkar could have