Israel and Iran have begun a new round of attacks, as the conflict between the two heavily armed rivals enters its fourth day.

The Israel-Iran conflict has escalated into its fourth day with mounting casualties, widening attacks, and no sign of diplomatic resolution.

Israel's air force achieved a "remarkable feat," said William Freer, a research fellow for national security at the U.K.-based Council on Geostrategy.

Smoke and missiles have lit up the skies in Israel and Iran in a fierce standoff triggered by fears over Tehran’s expanding nuclear program. Since June 13, hundreds of military strikes have been exchanged as the two nations remain locked in a conflict that shows no signs of abating.

The U.S. commander in chief again urged the Islamic republic to reach an agreement “before it’s too late.” Trump’s comments during the gathering of world leaders came shortly before Israel’s ambassador to the U.S. laid out what it would take from Tehran for his government to end its strikes on what he dubbed “the head of the snake.”

Israel has launched a series of strikes against Iran, targeting the country’s nuclear program and other military infrastructure. Iran has launched its own strikes in retaliation.