Blasts have been heard in Tehran and sirens have sounded in Israel as US president convenes National Security Council.

The Group of Seven nations expressed support for Israel in a statement issued late on Monday and labeled its rival Iran as a source of instability in the Middle East, with the G7 leaders urging broader de-escalation of hostilities in the region.

Donald Trump said his French counterpart Emmanuel Macron was wrong about the reason the US president left the G7 summit in Canada early, saying it was not to work on an Israel-Iran ceasefire.

Haifa and Tel Aviv struck by Iranian missiles as U.S. embassy in Israel directs government employees and families to shelter in place at home.

The conflict between Israel and Iran has wreaked considerable damage in both countries and caused casualties on both sides.

Iran has arrested dozens of people on suspicion of spying as fears grow in the Islamic Republic over the extent of its infiltration by Israel’s Mossad intelligence service.

Meanwhile Donald Trump says his early G7 exit has "nothing to do" with an Israel-Iran ceasefire, as fighting between the two nations enters a fifth day.

Oil prices have resumed their upward climb and U.S. futures are lower after Israel's military issued an evacuation warning to 330,000 people in Iran's capital Tehran.