Iran has long accused Israel of targeting its nuclear program through covert operations. Israeli officials, in turn, have hinted at potential strikes on Iran's nuclear sites. This exchange of threats that has intensified amid ongoing hostilities between the two nations since Israel's attacks on Hezbollah, a long-standing ally.

Rafael Grossi, head of the International Atomic Energy Agency, the U.N. nuclear watchdog, says the window of opportunity to diplomatically engage with Iran is beginning to "shrink."

U.N. atomic watchdog chief Rafael Grossi appealed to Iran's leadership on Tuesday to take steps to resolve longstanding issues with his agency a day before he arrives in the Iranian capital for crunch talks over its nuclear programme.