The governor of the southern city of Minab, where the school was located, said search-and-rescue efforts had ended.
The incident disrupted flights to the island, prompting the postponement of the meeting to a later date.
Nepal is holding fresh elections after the House of Representatives was dissolved following the unrest in the country last September.
Mr Araghchi also highlighted Iran’s inherent and inalienable right to defend its sovereignty, territorial integrity, and people under the UN Charter.
The IRGC said the “targeted and surprise” attacks were carried out using homegrown Kheibar ballistic missiles.
France has thrown its weight behind countries along the Persian Gulf and in Jordan in the Middle East against Iran’s provocations.
Mr Grossi warned that radiological releases with serious consequences cannot be ruled out.
The ministry said China’s embassies and consulates in nearby countries swung into action to help the affected.
Israeli warplanes carried out intensive airstrikes at dawn on Monday in Beirut’s southern suburbs.
The Iranian Red Crescent said on Monday that the death toll from U.S. and Israeli airstrikes on Iran since Saturday has risen to 555.
