On Thursday, Iran shot down a U.S. surveillance drone that it says was in its airspace. The U.S. military however, denied the claim, arguing that the drone was over international waters. And now, both sides are accusing the other of escalating tensions.

Both Iranian and U.S. officials have confirmed the shoot-down of the drone, but differ on where it was at the time it was shot.

A Centcom spokesman, Navy Capt. Bill Urban, said in a statement that the drone was shot down “while operating in international airspace over the Strait of Hormuz.”

“Iranian reports that the aircraft was over Iran are false,” Urban said. “This was an unprovoked attack on a U.S. surveillance asset in international airspace.”

Iran, meanwhile, is maintaining that the RQ-4A Global Hawk — a large drone, estimated to cost more than $100 million —  was in its airspace when it was shot down. Iranian Foreign Minister Javad Zarif said on Twitter that Iran will “take this new aggression” to the United Nations to “show that the US is lying about international waters.”

“We don’t seek war, but will zealously defend our skies, land & waters,” he wrote.

Trump tweeted Thursday that Iran “made a big mistake!” While meeting with Canadian Prime Minister Justin Trudeau, he was asked by reporters how he would respond to Iran, and he replied, “You’ll find out.”

When asked if he was willing to going to war with Iran, Trump responded, “You’ll find out. Obviously — obviously, obviously, you know we’re not going to be talking too much about it. You’re going to find out. They made a very big mistake.”

He then appeared to tamp down tensions somewhat, saying, “I have a feeling it was a mistake made by somebody that shouldn’t have been doing what they did. I think they made a mistake.”

“Are you saying you think it wasn’t intentional?” a reporter asked.

“I don’t know,” he replied. “I find it hard to believe it was intentional if you want to know the truth. I think that it could have been somebody who was loose and stupid that did it.”

It’s not clear exactly how the United States will respond based on these statements, but there is still concern that the attack could bring the two countries closer to war.

So how exactly did we get here?

Here’s a timeline of the escalated tensions between the two countries over the last two weeks:

June 13: An attack on two oil tankers in the Gulf of Oman

A series of explosions destroyed parts of two tankers in the Gulf of Oman last Thursday, and the United States said Iran was responsible. The two tankers were owned by Japan and Norway, and the attack took place as Japanese Prime Minister Abe Shinzo was visiting Iran. Abe was reportedly there to mediate between the United States and Iran.

Secretary of State Mike Pompeo — one of the more hawkish figures in the Trump administration — quickly blamed Iran for the attack, mere hours after investigation into the incident began. He said he believed Iran was directly responsible and the attack was not the work of any of its proxies.

“Iran is lashing out because the regime wants our successful maximum pressure campaign lifted,” Pompeo said. “No economic sanctions entitle the Islamic Republic to attack innocent civilians, disrupt global oil markets and engage in nuclear blackmail.”

Iran’s Zarif said the incident was “suspicious,” given that it happened at the same time as the Japanese prime minister’s visit, and called for a regional dialogue forum.

Later that evening, U.S. Central Command released a grainy video that it said showed an Islamic Revolutionary Guard patrol ship sailing up to one of the damaged tankers and removing an unexploded mine.

June 14: Japan distances itself from the U.S. assessment

The Japanese owner of one of the damaged tankers said the vessel was struck by a projectile and not by a mine, as U.S. officials claimed.

“We received reports that something flew towards the ship,” Yutaka Katada, president of Kokuka Sangyo, said at a press conference. “I do not think there was a time bomb or an object attached to the side of the ship.”

June 16: Pompeo doesn’t back off, blames Iran again

Pompeo appeared on Sunday news shows and once again blamed Iran for the attacks.

“The intelligence community has lots of data, lots of evidence,” he said in an interview with Chris Wallace on Fox News. “The world will come to see much of it, but the American people should rest assured we have high confidence with respect to who conducted these attacks as well as half a dozen other attacks throughout the world over the past 40 days.”

June 17: More U.S. troops sent to the Middle East, Iran announces it will soon break the nuclear deal limit

On Monday, then-Acting Defense Secretary Patrick Shanahan authorized an additional 1,000 troops to the Middle East to counter Iran, and said it was a response to Iran’s attacks on the oil tankers.

“The recent Iranian attacks validate the reliable, credible intelligence we have received on hostile behavior by Iranian forces and their proxy groups that threaten United States personnel and interests across the region,” he said in a statement announcing the deployment. “The United States does not seek conflict with Iran. The action today is being taken to ensure the safety and welfare of our military personnel working throughout the region and to protect our national interests. We will continue to monitor the situation diligently and make adjustments to force levels as necessary given intelligence reporting and credible threats.”

The deployment followed another 1,500 troops who were sent to the Middle East last month, due to what the Pentagon said were credible threats that Iranian proxy groups would attack U.S. personnel in the region.

Also on Monday, Iran announced that in 10 days, it would surpass the uranium stockpile limit in the 2015 nuclear deal. A spokesman for the country’s Atomic Energy Organization said that it would bypass the deal’s 300 kilogram limit, as European leaders urged calm.

The nuclear agreement — signed between the United States, Iran, the United Kingdom, Russia, China, France, and Germany — set limits on Tehran’s nuclear program in exchange for sanctions relief. Trump withdrew from the deal last year, and since then has reimposed sanctions on Iran, which constitutes a direct violation of the agreement.

The State Department urged Iran to abide by the deal Trump violated.

June 18: Acting defense secretary resigns

Shanahan resigned and withdrew his nomination for defense secretary, prolonging what is already the longest period in which the United States has gone without a confirmed defense secretary.

Trump said Shanahan withdrew his nomination because he wants to spend more time with his family. Shanahan’s nomination had been delayed due to a lengthy FBI background check, as reports of domestic violence within his family surfaced.

Army Secretary Mark Esper was named the acting defense secretary.

On the same day, Pompeo said the Trump administration is not seeking conflict with Iran and the recent troop deployment was meant simply as a deterrent to Iranian aggression.

“President Trump does not want war, and we will continue to communicate that message, while doing the things that are necessary to protect American interests in the region,” he told reporters at U.S. Central Command headquarters in Tampa, Florida.

June 19: U.S. military says mine fragments show Iran was responsible for attack on oil tankers

On Wednesday, the U.S. Navy said that limpet mine fragments it recovered from one of the two ships bore a “striking resemblance” to mines in Iranian military parades.

“The limpet mine that was used in the attack is distinguishable and also strikingly bearing a resemblance to Iranian mines that have already been publicly displayed in Iranian military parades,” Sean Kido, commanding officer of an explosive ordnance dive and salvage task group in the U.S. Naval Forces Central Command, told reporters.

June 20: Iran shoots down U.S. drone, both countries blame the other

Now you’re all caught up. We’ll see what happens next.

Iran made a very big mistake!

— Donald J. Trump () June 20, 2019