Israel and Iran launched fresh attacks on each other overnight into Sunday, stoking fears of a wider conflict after Israel expanded its surprise campaign against its main rival with a strike on the world's biggest gas field, Reuters reported.

Tehran called off nuclear talks that Washington had said were the only way to halt Israel's bombing, while Israeli Prime Minister Benjamin Netanyahu said the attacks were nothing compared with what Iran would see in the coming days.

The latest wave of Iranian attacks began shortly after 11:00 p.m. on Saturday (2000 GMT), when air raid sirens blared in Jerusalem and Haifa, sending around a million people into bomb shelters.

Around 2:30 a.m. local time (2330 GMT Saturday), the Israeli military warned of another incoming missile barrage and urged residents to seek shelter. Explosions echoed through Tel Aviv and Jerusalem as missiles streaked across the skies as interceptor rockets were launched in response. The military lifted its shelter-in-place advisory nearly an hour after issuing the warning, according to Reuters.