Israeli Prime Minister Benjamin Netanyahu vowed revenge after a hospital was struck by an Iranian ballistic missile, as the world waited for news of whether President Donald Trump would commit U.S. forces to Israel's campaign against Iran's nuclear program.

Back-and-forth attacks between Israel and Iran continued overnight as the conflict entered its seventh day, with an inactive Iranian nuclear reactor and an Israeli hospital among the sites hit.

Press secretary Karoline Leavitt says the US president believes there is a "substantial chance of negotiations" with Iran "in the near future".