As the world reacted to news of U.S. strikes on Iran's nuclear facilities, international officials largely responded with alarm and calls for restraint.

The strikes on Iran ushered in a period of high alert as the Pentagon braced for almost-certain retaliation against American forces in the region.

World leaders reacted to President Donald Trump's announcement Saturday that the U.S. had carried out a "very successful attack" on three nuclear sites in Iran, including Fordo.