Nuclear deal

July 25, 2015

Iran, the United States and other nations approve a deal in which Iran agrees to shift its nuclear program from weapons production to peaceful commercial use for 10 years. Iran allows international inspectors on its nuclear weapons sites.

In exchange, the United States and the United Nations Security Council lift energy, trade, technology and financial sanctions against Iran.

The pact, established during the tenure of President Barack Obama, is an executive agreement, not a treaty, which means it isn’t formally approved by Congress. Republicans oppose the deal and question its legality.

Leaving the deal

President Donald Trump regards the Iran pact as "stupid." Manuel Balce Ceneta, AP

October 2016

Presidential candidate Donald Trump says Iran should write the United States a thank you letter for “the stupidest deal of all time.” Trump says the United States will withdraw from the deal if he’s elected.

May 8, 2018

President Trump announces the withdrawal from the Iran deal. Iran, France, Britain and Germany say they will stay in the pact.

US increases pressure

U.S.-Iran relationship status: It's complicated The United States and Iran have been lobbing threats, fighting proxy wars, and imposing sanctions for decades. USA Today looks at over 60 years of this back-and-forth. Just the FAQs, USA TODAY

August-November 2018

The United States reimposes economic sanctions targeting Iran's energy, financial, shipping and shipbuilding industries. Iran says it will take unspecified actions regarding the nuclear deal if Britain, France, Germany, Russia and China don't help it engage in international trade.

April 8, 2019

Trump says he will designate Iran’s Islamic Revolutionary Guards as a foreign terrorist organization. The Pentagon opposes the change, saying it increases the possibility of retaliation against American military and intelligence personnel.

April 22

Trump says the United States will end exemptions on sanctions against countries buying oil from Iran, putting more pressure on Iran’s economy.

May 5

John Bolton, Trump's national security adviser, says the United States will send an aircraft carrier strike force and Air Force bombers to the Middle East. The deployment shows Iran that “any attack on United States interests or on those of our allies will be met with unrelenting force.”

Iran retaliates

May 8

Iran says it will increase its production of enriched uranium and heavy water.

May 12

Four oil tankers – two from Saudi Arabia, one from the United Arab Emirates and one from Norway – are attacked in the Persian Gulf. The United States says Iran is behind the attacks.

June 13

Two oil tankers – one from Norway, the other from Japan – are attacked in the Gulf of Oman. The United States blames Iran, which denies responsibility.

June 20

Iran shoots down a U.S. surveillance drone it says violated Iranian airspace. The U.S. Central Command says the aircraft was in international territory.

June 20

Trump orders retaliatory attacks against Iran but cancels the strikes shortly before they are to be launched. Four days later, he imposes more sanctions against Iran.

July 1

Iran says it’s exceeded the amount of low-enriched uranium it was allowed to build under the 2015 agreement.

US-Iranian tensions rise

July 4

Gibraltar and British marines seize the Iranian oil tanker Grace 1 at the request of the United States. The ship is suspected of illegally transporting oil to Syria.

July 18

Trump says a U.S. Navy vessel shot down an Iranian drone that came within 1,000 of the ship.

July 20

Iran seizes the British-owned oil tanker Stena Impero near the Strait of Hormuz.

July 22

Iran says it’s arrested 17 Iranians and charged them with spying for the United States. News reports say some of the Iranians were executed.

General killed after clashes in Iraq

. Google Earth, Maxar Technologies

Dec. 27

A U.S. civilian contractor is killed and several troops injured in a rocket attack in Kirkuk. The Iran-backed militia group Kataeb Hezbollah is blamed.

Dec. 29

U.S. planes bomb three sites in Iraq – one of them in Al-Qaim – and two sites in Syria. Twenty-five people are killed. The sites are tied to Kataeb Hezbollah.

Dec. 31

Militia-backed protesters attack the U.S. Embassy in Baghdad.

Jan. 2

Iranian military leader Qasem Soleimani and five others are killed in a U.S. drone strike at Baghdad airport. U.S. officials call it a "defensive action," saying Soleimani planned attacks on U.S. diplomats and troops.

Iraq retaliates for general's death

Jan. 8

Iran launches multiple rocket attacks against U.S. troops at two coalition bases in Iraq – al Assad and Erbil. President Trump, addressing the nation on Wednesday, says no Americans were harmed and that minimal damage was sustained.

Iranian state media say the attacks are in response to Soleimani's killing. It says Iran will de-escalate if the U.S. does not retaliate but will re-engage if it does.