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

When asked at a news briefing Monday about the prospect of a ceasefire, however, Israeli Prime Minister Benjamin Netanyahu indicated he was not interested in one, according to NBC News. Netanyahu said Israel is "not backing down" from eliminating Iran's nuclear program.

The conflict between Israel and Iran has forced many countries in the Middle East to close their airspace, as Israeli jets and Iranian exploding drones and missiles fly over their night skies.

The U.S. military has reportedly moved a large number of refueling aircraft to Europe to provide options to Trump.

White House press secretary Karoline Leavitt cited the Israel-Iran conflict in announcing Trump's plans to depart the Group of Seven summit in Canada a day early.

President Donald Trump signaled Monday that the ongoing conflict between Israel and Iran was intensifying rapidly, announcing he would return to Washington a day early from the Group of 7 summit in Canada to monitor developments after issuing an ominous warning to Iranians to “immediately evacuate” their capital city.

"Israel is being assisted this way or that way by some Iranians," ex-Israeli National Security chief Giora Eiland told Newsweek.

Global energy executives gathered in the Malaysian capital on Monday for an industry conference with an eye on the dramatic escalation in the conflict between Israel and Iran, which has fuelled worries that it could widen and disrupt supply.