U.S. President Donald Trump announced Tuesday that a ceasefire between Israel and Iran was now in effect and publicly urged both countries not to violate the agreement, following 12 days of hostilities and high-level mediation efforts involving Qatar.

“Please Do Not Violate It,” Trump Warns

In a Truth Social post, Trump declared: “THE CEASEFIRE IS NOW IN EFFECT. PLEASE DO NOT VIOLATE IT!” His announcement came just hours after Iran fired six waves of missiles.

Although some missile barrages continued just before the ceasefire took effect, Iranian media later confirmed that Tehran had launched its last strikes prior to the truce deadline.

Trump, Qatar, and the 12-Day War

The ceasefire follows a complex diplomatic effort. A senior White House official confirmed Trump personally brokered the deal during a call with Israeli Prime Minister Benjamin Netanyahu. Qatar’s Prime Minister Sheikh Mohammed bin Abdulrahman Al Thani then relayed the proposal to Tehran.

Vice President JD Vance, Secretary of State Marco Rubio, and special envoy Steve Witkoff were reportedly in contact—directly and indirectly—with Iranian counterparts.

Trump congratulated both nations on having “the Stamina, Courage, and Intelligence” to end what he called “THE 12 DAY WAR.”

Iran’s Conditional Acceptance

Iranian Foreign Minister Abbas Araqchi had earlier warned that hostilities would only stop if Israel ceased “illegal aggression” by 4 a.m. Tehran time. He emphasized that Iran’s final decision on halting operations would depend on Israel’s restraint.

While Iran denies seeking nuclear weapons, JD Vance stated that U.S. and Israeli strikes over the weekend had destroyed Iran’s capability to build one: “Now Iran is incapable of building a nuclear weapon with the equipment they have,” he said on Fox News.

Market Relief and Regional Aftermath

Following the announcement, S&P 500 futures rose and oil prices fell, reflecting reduced fears of regional energy disruptions. However, much of Tehran remains evacuated after days of airstrikes, and skepticism lingers over whether the ceasefire will hold amid unresolved tensions.