VIENNA — International Atomic Energy Agency (IAEA) chief Yukiya Amano will be in Tehran on Thursday to discuss monitoring sensitive nuclear sites with senior officials as major powers and Iran seek a breakthrough in forging a lasting nuclear agreement. Iran and world powers gave themselves an extra week on Tuesday to reach an accord curbing Iran's nuclear program in exchange for sanctions relief, but US President Barack Obama warned there would be no deal if all pathways to an Iranian nuclear weapon were not cut off. Western countries suspect Iran of seeking the capability to make a nuclear weapon. Tehran says its program is peaceful. Major sticking points that remain between the two sides include access for UN nuclear inspectors to Iranian military sites, the pace and timing of sanctions relief for Iran and IAEA queries about Tehran's past activities that may have been related to atomic weapons research. Amano will meet Iranian President Hassan Rohani and other senior officials, the IAEA said in a statement on Wednesday. "Discussions are expected to address ongoing cooperation between the IAEA and Iran," the IAEA said, and would cover "how to accelerate the resolution of all outstanding issues related to Iran's nuclear program, including clarification of possible military dimensions (PMD)." Red lines For more than a week, the sides have been working into the night trying to break an impasse in talks they feel have never been closer to success. Western diplomats say they are nearing a resolution on access, although Iranian officials maintain that military sites are off-limits due to a red line set by Supreme Leader Ayatollah Ali Khamenei. Iran has been accused of stonewalling the IAEA probe on its past activities, and Western officials have said some of the sanctions relief would depend on Iran's cooperation. But diplomats say Iran will be reluctant to open up to IAEA investigators until the punitive sanctions are lifted. Rohani said on Tuesday Iran would resume suspended atomic work if the West broke its promises. In a positive sign for the talks, Western diplomats said an IAEA report due out later on Wednesday would show that Iran had complied with a preliminary deal to reduce its low-enriched uranium stockpile. An IAEA report in May said the stockpile had increased above the required level, but Tehran met a June 30 deadline to reduce it. — Reuters