The comments by General Mohammad Ali Jafari came as some 200 hard-liners protested in Tehran against the framework deal reached last week in Switzerland. Jafari's endorsement likely will isolate those still opposing the deal further amid the widespread support negotiators have received and may smooth any potential parliamentary vote over it.
"With God's grace, the revolutionary children of Islamic Iran have succeeded in defending the rights of the Iranian nation and the Iranian nation and the Guard appreciate their honest political efforts," Jafari was quoted as saying on state TV's website.
Iran's top leader Ayatollah Ali Khamenei, who has the final say on all major issues, including the nuclear program, has backed the negotiators, further stepping up the pressure on remaining hold-out hard-liners.
The rally today by 200 hard-line protesters took place in front of the parliament in the Iranian capital as Foreign Minister Mohammad Javad Zarif briefed lawmakers there in a closed-door session. Iran's official IRNA news agency reported that the protesters launched their demonstrations without the permission of authorities.
The deal, which is to be finalized by June 30, is to curb Iran's bomb-capable technology while giving Tehran quick access to bank accounts, oil markets and financial assets blocked by international sanctions.
The West long has feared Iran's nuclear program could allow it to build an atomic bomb. Iran has said its program is for peaceful purposes.