China suggested the US use its influence with Israel to stop the conflict with Iran from spilling over, a sign Beijing is becoming increasingly concerned about the stability of a region it relies on for energy supplies.

U.S. President Donald Trump said his early departure from the G7 summit was owed to "much bigger" things than planning a ceasefire between Tel Aviv and Tehran. G7 leaders affirmed unified support for Israel and condemned Iran for being the "principal source of regional instability and terror.

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