The eight candidates approved by the 12-member Guardian Council to have their names on the next Friday's ballot held their third and final debate Friday, focusing on foreign policy.
Radio Free Europe/Radio Liberty published an English-language live blog of the Friday debate, which was described as cantankerous at times.
Former Foreign Minister Ali Akbar Velayati blamed rival candidate and chief nuclear negotiator Jalili for not doing enough to protect Iran's right to a nuclear program.
Jalili this year led an Iranian delegation during talks in Kazakhstan with the five permanent members of the Security Council. Talks were described as amicable though negotiations yielded few results.
Velayati said he'd protect Iran's right to nuclear research using "intelligence diplomacy" if elected president, RFE/RL reports. He said if Jalili were doing his job effectively, Iran would be able to escape economic sanctions.
Jalili was quoted by Iran's state-funded broadcaster Press TV as saying this week Iran wouldn't "retreat one iota from our basic [nuclear] rights."
Iran has the right to peaceful nuclear research as a party to the Nuclear Non-Proliferation Treaty.
The U.S. government this week enacted a series of economic sanctions on Iran in response to growing nuclear concerns. A June report from the International Atomic Energy Agency said there may be a military dimension to Iran's nuclear program.