Meanwhile, the U.N.'s atomic watchdog agency delivered a quarterly assessment of Iran's controversial nuclear program, reporting that the Islamic Republic had granted inspectors access to sensitive research sites but has continued to stonewall efforts by international inspectors to examine past alleged weapons-related nuclear research. During a pre-sermon speech at weekly prayers in Tehran, the Iranian capital, President Mahmoud Ahmadinejad did not explicitly name his reformist rivals, such as former prime minister MirHossein Mousavi and former parliamentary speaker Mahdi Karroubi, but he left little doubt he was speaking about them in calling for the punishment of those he termed the 'masterminds' of weeks of public unrest that followed his disputed June 12 re-election victory. 'The most important task for the judiciary and security bodies is to deal seriously with the leaders and masterminds' of the unrest, he said, undermining the peacemaking tone set by Khamenei earlier this week. 'All of those who organized and instigated (the riots) and followed the enemy line have to be seriously confronted. The masterminds of the riots should by no means enjoy any immunity.' The crowd inside the Tehran University venue chanted, 'Execution for the ringleaders!' Detainees in an ongoing televised trial have accused reformist leaders, including Mousavi, of being behind the unrest and collaborating with Iran's foreign rivals. Ahmadinejad's comments appeared to confirm reports that he has personally been behind efforts to haul leading political opponents into court. On Wednesday, Khamenei made a conciliatory speech welcoming the opposition back into the nation's political fold and rejecting the assertion that they were backed by foreigners. Ahmadinejad's decision to risk riling Khamenei, whose staunch loyalists make up much of his political base, baffled observers. The president faces a huge challenge in coming days over his proposed Cabinet, which many members of his own conservative camp in parliament have vowed to forcefully scrutinize before voting to approve. While a harsh security crackdown appears to have quelled the massive public protests that erupted amid allegations of vote-rigging in the presidential elections, it has failed to quiet increasingly daring reformist and moderate politicians who continue to defy hard-liners' threats to have them jailed. 'We will not budge regardless of all the pressures aimed at dislodging reformists,' former President Mohammad Khatami, a reformist, said at a meeting of reformist political activists Thursday night. 'We can no longer defend our Islamic Republic against rigid-minded, extremist and inhumane groups working under the name of Islam.' Analysts said Ahmadinejad may be seeking to undermine any effort at accommodating an the opposition movement that Mousavi and others are seeking to build and legitimize, convinced that any tolerance of his domestic political enemies would only come at a cost to his political power. The post-election domestic dysfunction also has complicated efforts by the Obama administration to engage Iran in negotiations over its nuclear ambitions. Iran claims it is refining uranium solely for civilian energy purposes, but the U.S. and Western allies believe its ultimate goal is to produce nuclear weapons. Friday's quarterly report by the International Atomic Energy Agency, or IAEA, to its governing board suggested Iran had continued producing reactor-grade enriched uranium at about the same pace as before the June presidential election and was operating about the same number of centrifuges in total, while having installed at least 1,300 new ones at its facility in Natanz since May. According to the report, which was obtained by the Los Angeles Times, Iran says it has amassed at least 3,318 pounds of reactor-grade uranium, more than the 2,400 or so pounds necessary to build a single nuclear bomb if Iran was to break its treaty obligations and further enrich its supply to weapons-grade standards. 'What we've seen has been a straight line up,' said Jacqueline Shire, an arms control expert at the Institute for Science and International Security in Washington. The report shows 'a steady trajectory, with no additional expansion except for the sudden rise of installed centrifuges.' The report said Iran granted a long-standing request to allow the international inspectors to visit a heavy water nuclear plant in Arak; allowed the installation of additional surveillance equipment at the Natanz facility; gave better access to records; and agreed to better accommodate surprise inspections. But just days before world powers meet in Frankfurt, Germany, to discuss possibly ratcheting up economic sanctions on Iran, the report took Iran harshly to task for what it describes as the nation's refusal to clear up questions about the so-called 'alleged studies,' a set of classified documents that purport to show that Iran was pursuing activities consistent with a clandestine nuclear weapons program until six years ago. Iranian officials have described the documents as forgeries created by Iran's enemies abroad. But the report says the evidence came from multiple sources over different time periods and is 'sufficiently comprehensive and detailed that it needs to be addressed' to remove doubts 'about the exclusively peaceful nature of Iran's nuclear program.' The report said that 'Iran had not adequately addressed the substance of the issues,' instead focusing 'on the style and form' of the documents. It calls on Iran to clear up questions about a 'foreign national with explosives expertise' who visited Iran and took part in tests consistent with atomic weapons development and also to grant access to factories allegedly involved in missile design. Special correspondents Ramin Mostaghim in Tehran, and Julia Damianova in Vienna, Austria, contributed to this report. 