An Iranian negotiator on Sunday denied accepting military site inspections as part of a nuclear deal with world powers, a delicate issue in talks that must be concluded by the end of June.

Abbas Araghchi, who is also deputy foreign minister, made the remarks as he briefed a parliamentary committee on the progress of the talks with the P5+1 -- Britain, China, France, Russia and the United States plus Germany.

"In his report, Mr. Araghchi said that inspections of military sites have been accepted but the inspections are regulated and will be seriously managed," ultra-conservative lawmaker Javad Karimi-Ghodoussi was quoted as saying by Fars news agency.

The remarks appeared to contradict those of supreme leader Ayatollah Ali Khamenei, who said this week that inspections of military sites and interviews of scientists by foreign experts were excluded from a framework nuclear agreement.

Araghchi denied the lawmaker's comments on his Instagram page.

"What can we do except put the fate of Karimi-Ghodoussi and Fars in the hands of God?" he wrote alongside a picture of a Fars headline that read: "We accepted the inspection of military sites".

Araghchi said later that during the briefing both he and Foreign Minister Mohammad Javad Zarif reiterated their "objection to inspections or visits to any military centres or interviews with our nuclear scientists".

"We presented necessary explanations... regarding security measures which countries implementing the protocol usually take in order to protect their military, nuclear and industrial information and prevent spying," he said in a statement from the ministry.

The United States says Iran has agreed in principle to enhanced inspections of its nuclear sites by the International Atomic Energy Agency (IAEA), particularly under the Additional Protocol that allows snap inspections.

"The exact details of the inspection regime are still being worked out," said US State Department spokeswoman Marie Harf.

She expressed hopes for "a solution that will give us and the IAEA the assurances we need with regard to access (to the sites) and transparency" of the Iranian nuclear programme.

Tehran denies any foreign access to its military facilities, in order to protect national "military or economic secrets".

The official IRNA news agency quoted parliamentary spokesman Behrouz Nemati as saying "it will not be like the Americans can inspect any place at any time" and "these inspections will be regulated".

The long-running nuclear talks between Iran and the P5+1 are aimed at preventing the Islamic republic from getting the bomb, in exchange for the easing of international economic sanctions.

The parties have until June 30 to finalise the deal.