(CNN) — President Donald Trump announced Saturday evening that US military forces had dropped bombs on three Iranian nuclear facilities, ending a weeklong deliberation period over joining Israel’s campaign against Tehran and thrusting the United States squarely into an escalating Middle East conflict.

“We have completed our very successful attack on the three Nuclear sites in Iran, including Fordow, Natanz, and Esfahan. All planes are now outside of Iran air space,” Trump wrote on Truth Social.

Trump added a “a full payload of BOMBS was dropped on the primary site, Fordow.”

He ended his message with a call for peace.

“There is not another military in the World that could have done this,” Trump wrote. “NOW IS THE TIME FOR PEACE!”

Trump announced in a subsequent post that he will address the nation at 10 p.m. ET Saturday.

“This is an HISTORIC MOMENT FOR THE UNITED STATES OF AMERICA, ISRAEL, AND THE WORLD. IRAN MUST NOW AGREE TO END THIS WAR. THANK YOU!” Trump wrote in a Truth Social post. He also reposted a social media post that said “FORDOW IS GONE.”

The decision to target Iran directly significantly ratchets up tensions, and amounts to one of the most consequential choices of Trump’s young second presidency.

It’s the first time in several decades — since the Iranian revolution in 1979 — that an American president has deployed Air Force assets to target major facilities in the country.

American B-2 bombers were used in the operation to target the three sites, according to a source familiar with the matter.

B-2 bombers are the only plane capable of carrying the Massive Ordinance Penetrator, which experts have highlighted as the only type of bomb potentially capable of destroying Iran’s underground Fordow nuclear facility. Each B-2 bomber is able to carry two of these “bunker buster” bombs, which weigh an impressive 30,000 pounds each.

The move to target the Fordow facility in particular, which successive US presidents had considered but ultimately decided against, will now insert Trump directly into a growing crisis that he had once hoped to defuse through diplomacy.

As Trump was mulling his decision, Iran had vowed to retaliate to any US aggression, and American military assets had begun massing in the region to prepare for any retaliatory action from Iran.

This story has been updated with additional information.