The pontiff told the faithful on Sunday that the nuns "gave their blood for the church" and that they were not only victims of the attackers but also of "this indifference of globalisation".
The nuns were among 16 people killed on Friday by gunmen who stormed a retirement home run by a charity established by Mother Teresa.
Meanwhile the Indian Foreign Minister announced on her twitter account that an Indian priest was abducted during the attack.
Sushma Swaraj said officials were trying to establish the location of Fr Tom Uzhunnalil. She said he had been "abducted by terrorists".
No one claimed responsibility for the attack.