President Donald Trump vetoed Israel’s plan to kill Iran’s Supreme Leader Ayatollah Ali Khamenei, according to a U.S. official familiar with the matter.

Israel unleashed airstrikes across Iran for a third day Sunday and threatened even greater force as some Iranian missiles evaded Israeli air defenses.

Iran has told the United States and UK that it could retaliate if the countries aid Israel in attacks amid fears the Middle East will descend into war.

Israel's defense minister warned Saturday that "Tehran will burn" if Iran continues firing missiles, as the countries traded blows.

Tensions in the Middle East have intensified as Iran's state television announced that more missiles are headed toward Israel.

It was not immediately possible to verify the competing claims or confirm the identities of those killed.

At least 31 people were killed and over 170 were wounded Sunday while on their way to receive food in the Gaza Strip, health officials and witnesses said.

Israel launched "extensive" new ground operations in the Gaza Strip while airstrikes in its new offensive killed at least 103 people.