Israel on Saturday launched what it described as a “preventative attack” against Iran, with the country’s defence minister declaring a state of emergency nationwide.Israel’s defence minister Israel Katz made the announcement as thick smoke was seen rising from an explosion in downtown Tehran, Iran’s capital. Iranian state television acknowledged the blast but did not provide further details.At the same time, sirens sounded across Israel. The Israeli military said the move was a “proactive alert to prepare the public for the possibility of missiles being launched toward the state of Israel.”The developments come amid heightened regional tensions. Earlier on Friday, the US State Department authorised non-emergency personnel and their family members to leave Israel, citing unspecified “safety risks”, CBS News reported.The updated advisory comes as Washington continues negotiations with Tehran over a potential nuclear deal. Iran hopes an agreement would avert a possible American military assault, which President Donald Trump has previously signalled by ordering a significant US military deployment to the Middle East.Trump has earlier threatened to attack Iran if no deal to rein in its nuclear programme is reached.This is a developing story.