Director General of the International Atomic Energy Agency (IAEA) Rafael Mariano Grossi speaks during a press conference in Abu Dhabi, United Arab Emirates, Tuesday. Reuters-Yonhap

VIENNA — The U.N. nuclear watchdog sent a report to member states on Thursday with no major changes to its assessment of Iran's nuclear programme, despite three months of U.S.-Israeli war with the stated aim of preventing Iran from building an atomic bomb.

In its first report into Iran's nuclear programme since the day before the United States and Israel launched air strikes on Iran at the end of February, the IAEA repeated calls for Tehran to explain the fate of stockpilesof enriched uranium. The uranium has been unaccounted for since an earlier U.S.-Israeli bombingcampaign a year ago targeted Iran's main nuclear sites.

U.S. President Donald Trump and Israeli Prime Minister Benjamin Netanyahu repeatedly cited destroying Iran's nuclear programme as one of their main aims in launching fresh strikes at the end of February.

Iran's enriched uranium stockpile has been a major sticking point in negotiations between the United States and Iran to end the war, with Trump insisting Iran give it up. Efforts have lately focused on a preliminary deal that would leave nuclear issues for later.