Archfoes Iran and Israel traded deadly blows on Monday, with Israel hitting targets deep inside the Islamic Republic and Tehran's strikes killing at least 11 on day four of an escalating conflict.

After decades of enmity and a prolonged shadow war, Israel on Friday launched a surprise aerial campaign targeting sites across Iran, saying the attacks aimed to prevent it from acquiring atomic weapons – a charge Tehran denies.

Israel's strikes have so far killed at least 224 people, including top military commanders, nuclear scientists and civilians, according to Iranian authorities.

In retaliation, Iran's Revolutionary Guards said it had "successfully" struck Israel with a salvo of missiles and warned of "effective, targeted and more devastating operations" to come.

The Iranian attacks hit Tel Aviv, Bnei Brak, Petah Tikva and Haifa – with shattered homes, smouldering wreckage and stunned residents picking through debris.