"The role of frogmen was confirmed by Headley when the Indian investigators interrogated him in the US," a senior official said.
Kasab had confessed that the 10 terrorists, including himself, who attacked Mumbai received training in swimming and underwater diving from Pakistan Navy frogmen.
Officials said the Indian investigators so far had no plan to interrogate Headley's accomplice Tahawwur Hussain Rana, a Canadian citizen of Pakistani origin, as his involvement in the Mumbai attack conspiracy was limited to providing finance.
“If necessary, we may interrogate Rana also, though we have no immediate plan to do so," an official said.
2008 Mumbai attacks, which drew widespread condemnation across the world, began on Nov 26, 2008 and lasted until Nov 29, killing at least 173 people and wounding at least 308.