"Such a control room could not have been set up without some kind of state support," he said at a press conference here.
Jundal, 30, arrested here on June 21 on his arrival from Saudi Arabia, had found a "very safe haven" in Pakistan, he said.
Jundal is being interrogated by Delhi Police and security agencies to ascertain all aspects of the conspiracy behind the 2008 Mumbai attacks that left 166 dead including some foreigners.
About the presence of others in the control room and whether Saeed was also there, Chidambaram said "Yes, others were present and we think one of them was Hafiz Saeed."
He termed Jundal's arrest as an "important development" as far as the investigations in the 26/11 Mumbai terror case were concerned.
"In fact many of the missing pieces of the 26/11 conspiracy are now known to us through interrogation of Abu Jundal. He was a key operative, he was assigned the key responsibility of putting the 10 terrorists to intensive training and the customs followed by Mumbaikars.
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"He was the key person who briefed the 10 persons including (Ajmal) Kasab and he had an important role in the control room," he said.
Taking a potshot at Pakistan's Interior ministry chief Rehman Malik that Jundal was an Indian, he said, "I agree with Rehman Malik that Abu Jundal is an Indian and perhaps he was radicalised in India. I admit that.
"Equally, Pakistan should admit that Abu Jundal did go to Pakistan, that Abu Jundal was part of the group which trained and prepared Kasab and nine others and that Abu Jundal was in the control room and one of the masterminds and handlers of the attack.
"Just as we admit the facts Pakistan too should admit the facts," he said. More