"Iran's key nuclear enrichment facilities have been completely and totally obliterated. Iran, the bully of the Middle East, must now make peace," Trump said in a televised address to the nation from the White House after the strikes.

Here is a roundup of the key reactions:

- Iran: 'Everlasting consequences' -

Iran's Foreign Minister Abbas Araghchi on Sunday condemned the US attacks as "outrageous" and said his country has a right to defend its sovereignty.

"The events this morning are outrageous and will have everlasting consequences," he posted on X, adding that the attacks were "lawless and criminal" behavior.

"In accordance with the UN Charter and its provisions allowing a legitimate response in self-defense, Iran reserves all options to defend its sovereignty, interest, and people," the foreign minister said.

Iran's atomic energy organization also called the US attacks "a barbaric act that violates international law."

"The Atomic Energy Organization of Iran assures the great nation of Iran... it will not let the path of development of this national industry (nuclear), which is the result of the blood of nuclear martyrs, be stopped," it said in a statement published by state media.

- Israel: 'Change history' -

Israeli Prime Minister Benjamin Netanyahu congratulated Trump, saying the attacks will "help lead the Middle East and beyond to a future of prosperity and peace."

"Your bold decision to target Iran's nuclear facilities with the awesome and righteous might of the United States will change history," Netanyahu said in a video message, adding that the attacks demonstrated "America has been truly unsurpassed."

He also told Israelis that his promise to destroy Iran's nuclear facilities had been "fulfilled."

- Hamas: 'Brutal aggression' -

Palestinian militant group Hamas condemned the "blatant US aggression against the territory and sovereignty of the Islamic Republic of Iran."

"This brutal aggression is a dangerous escalation," Hamas said, calling the attack "a flagrant violation of international law, and a direct threat to international peace and security."

- UN: 'Dangerous escalation' -

UN Secretary-General Antonio Guterres called the strikes a "dangerous escalation in a region already on the edge."

"At this perilous hour, it is critical to avoid a spiral of chaos," Guterres said in a statement. "There is no military solution. The only path forward is diplomacy. The only hope is peace."

- Democrats: 'Unilateral military action' -

The top Democrat in the US House of Representatives accused Trump of pushing the United States toward war.

"President Trump misled the country about his intentions, failed to seek congressional authorization for the use of military force and risks American entanglement in a potentially disastrous war in the Middle East," Congressman Hakeem Jeffries said in a statement.

"Donald Trump shoulders complete and total responsibility for any adverse consequences that flow from his unilateral military action."