Some 400 Jamaat-ud Dawa members held the ceremony today in the northwestern city of Peshawar. Similar ceremonies were also held in Quetta, Hyderabad and Karachi.
Jamaat-ud Dawa is a terror organization widely believed to be front group for Lashkar-e-Taiba, blamed for the 2008 attacks in the Indian city of Mumbai.
The funeral prayers took place even though Mansour's body is still in the hands of Pakistani authorities for DNA testing.
The crowd in Peshawar also chanted US slogans burned an American flag.