Israeli Prime Minister Benjamin Netanyahu vowed on Sunday his country would achieve victory after the military said it shot down almost all the more than 300 drones and missiles launched by Iran in a sharp escalation of the Middle East conflict.

Iran launched explosive drones and fired missiles at Israel late on Saturday in its first direct attack on Israeli territory, a retaliatory strike that raised the threat of a wider regional conflict, as the U.S pledged "ironclad" backing for Israel.

Israeli Prime Minister Benjamin Netanyahu said in a statement on Saturday that Israel had been preparing for an attack from Iran.

"In recent years, and especially in recent weeks, Israel has been preparing for a direct attack by Iran," he said.

"Our defensive systems are deployed; we are ready for any scenario, both defensively and offensively. The State of Israel is strong. The IDF is strong. The public is strong," he said.

Netanyahu thanked the US, Britain, France and its other allies for "standing alongside Israel."