In several waves of attacks, the two sides targeted each other for the first time since a ceasefire took effect in April.

Pakistan, Qatar, Turkey and Egypt, have been working to help bridge differences between the U.S. and Iran and encourage efforts aimed at reopening of the Strait of Hormuz.

U.S. efforts for a truce in Lebanon appear to have stalled. Israel accused Hezbollah of firing at Israeli territory. Iran swiftly retaliated.

White phosphorus is not banned under international law, but can "create cruel injuries" and indiscriminate harm in civilian areas.

The Israeli and Lebanese governments have agreed to implement a ceasefire, after weeks of deadly fighting between Israel and Hezbollah had imperiled broader negotiations between the U.S. and Iran to end their conflict.