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

President Donald Trump urged civilians living in Tehran to evacuate the Iranian capital "before there is nothing left."

Markets are concerned about Iran's frequent threats to blockade the Strait of Hormuz, just as the US heads into peak summer demand season.

President Donald Trump in about eight hours went from suggesting a nuclear deal remained “achievable” to urging Tehran’s 9.5 million residents to flee for their lives.

U.S. stock futures slipped and oil prices rose on Tuesday, as investors were rattled by U.S. President Donald Trump's call for everyone to evacuate Tehran with the fifth-day of Israel-Iran fighting sowing fears of a broader regional conflict.

TEL AVIV, Israel (AP) — Iran fired a new wave of missile attacks on Israel early Monday, killing at least five people, while Israel claimed in the fourth day of the conflict that it had now achieved “aerial superiority” over Tehran and could fly over the Iranian capital without facing major threats.

The strikes came after the Israeli military said it had carried out fresh strikes on Iran nuclear infrastructure sites.

In his first public comments on the Israeli strikes against Iran, the U.S. president said Tehran had brought the destruction on itself and must continue nuclear talks.