Iran’s Supreme Leader Ali Khamenei has ruled out foreign inspections of nuclear sites in a speech given just a week before the deadline on Tehran reaching a comprehensive nuclear agreement with world powers.

The Islamic Republic’s head of state gave a speech broadcast throughout Iran, which appeared to go back on some of the concessions agreed to in the interim deal reached on 2 April, casting doubt on the two sides’ ability to reach an agreement next week.

“Freezing Iran’s research and development for a long time, like 10 or 12 years, is not acceptable,” Khamenei was quoted as saying by Reuters.

“All financial and economic sanctions imposed by the UN Security Council, the US Congress or the US government should be lifted immediately when we sign a nuclear agreement,” he added, reinforcing Iran’s position on a key negotiating point.

Iran and the P5+1 group of world powers – the US, France, Germany, the UK, China and Russia – are aiming to reach an agreement by 30 June to allow Tehran relief from economic sanctions in exchange for limits on its nuclear development programme.

According to the US State Department, Iran agreed in April that the final deal would give UN inspectors access to suspected nuclear sites and that parts of its uranium enrichment programme would be halted.

“Inspection of our military sites is out of the question and is one of our red lines,” Khamenei said in his speech.

Meanwhile, the Tehran Times reported that the Iranian parliament has approved the details of a bill to “safeguard the country’s nuclear achievements”.

The bill states the government would only agree to limits on its nuclear programme if all sanctions against the Islamic Republic are removed on the day the deal takes effect.

It also stresses that the UN’s International Atomic Energy Agency (IAEA) would only be allowed to conduct “standard monitoring activities” at Iran’s nuclear sites, ruling out any inspections of military, security or sensitive non-nuclear facilities.

The details of the bill were passed with 213 votes in favour out of a total of 244 votes, the Iranian newspaper reported.

These developments could make it more difficult for Tehran’s negotiating team to meet the requirements of the P5+1 group to reach a comprehensive agreement.

Officials on both sides said in late June that talks could overrun the 30 June deadline as negotiators try to overcome these key sticking points.

Efforts to reach a framework deal overran the deadline by two days before an agreement was finally reached on 2 April.