The comments appeared to be directed at Persian Gulf countries such as Saudi Arabia and the United Arab Emirates — close allies of the Trump administration and, alongside Israel, the most vocal outside critics of the agreement that Iran reached with the United States and five other nations in 2015.
Khamenei also mentioned the letter during an event earlier Wednesday at Farhangian University in Tehran.
“A couple of days ago, Trump wrote a letter to the leaders of the Arab world. We have that letter,” the ayatollah said. “In the letter, he says I have spent $7 trillion on you, you have to do [what I say]. You spent this money to rule over Iraq and Syria. You couldn’t. To hell with it. He says you should do it and says Iran 'should' do it, too.”
The letter has not been publicly acknowledged by the White House, and a spokesman for the National Security Council said it could not comment on presidential correspondence. However, a senior administration official, who spoke on the condition of anonymity because he did not have permission to discuss the matter publicly, said the Trump administration sent a letter to Persian Gulf Arab allies about two weeks ago.
The letter not only urged the U.S. allies to do more in the region's hot spots, such as Syria, but also sought a quick resolution to an ongoing dispute between a Saudi-led bloc and Qatar. The administration official said it was a formal follow-up to talks that Trump had with regional leaders over the past two months and aligned with his public comments on the issues.
Saudi Arabia, in turn, privately responded to the letter, the official said, and gently pushed back on the pressure about Qatar specifically. A spokeswoman for the Saudi Embassy in Washington did not respond to a request for comment.
It is not clear how Iran's supreme leader found out about the letter, the official said. Theodore Karasik, a senior adviser with Washington-based Gulf State Analytics, said it was “significant because the content tells the supreme leader what Iran is about to face from the U.S.” and suggested that the letter could have been passed on by a regional power such as Kuwait, Qatar, Oman or Jordan or even an outside power like Russia.
Trump has said publicly that gulf allies should do more in the region and not rely on the United States as much as they do. He has also brought up the $7 trillion figure multiple times — saying in February, for example, that the United States has spent “$7 trillion in the Middle East,” which he called “a mistake.”
The dollar figure is inaccurate: Trump is thought to be referring to a study from Brown University that included future costs not only for the wars in Iraq and Syria but also in Afghanistan and such expenses as veterans' care for nearly 40 more years.
Last month, Trump publicly criticized Middle Eastern countries that relied on U.S. support as French President Emmanuel Macron visited Washington. “Countries that are in the area, some of which are immensely wealthy, would not be there except for the United States and, to a lesser extent, France,” Trump said at the time at a news conference at the White House.
“They wouldn't be there except for the United States,” he added. “They wouldn't last a week. We are protecting them. They have to now step up and pay for what is happening.”
Though Trump did not mention any countries specifically, it was widely assumed that he was talking about the United Arab Emirates. Trump has called on gulf allies to pick up the burden in the Syrian conflict as the United States winds down its military presence. During a phone call with Saudi King Salman in December, Trump asked Saudi Arabia for $4 billion for the effort in Syria.
Khamenei decried Trump's April comments, calling them a “humiliation for Muslims” and saying they showed how “Muslims should stand firmly against the U.S. and other domineering powers’ bullying.”
Trump's remarks did stir discomfort among Persian Gulf allies, some of whom argued that his tone was disrespectful. Abdulkhaleq Abdulla, a well-known UAE political commentator, was among those angered by the remarks. He retorted in a tweet that his country and others will survive after Trump is gone.
The leaders of Saudi Arabia and the UAE have aggressively pursued close relations with Trump, viewing his administration as a welcome change after President Barack Obama sought better ties with Iran. Saudi Arabia and the UAE are at odds with Iran over a number of issues, including Tehran's deep involvement in the Syrian conflict and claims that Iran has backed rebels in Yemen.
After Trump announced his decision to withdraw from the Iran deal on Tuesday, Saudi Arabia's ambassador to Washington said the kingdom “fully supports the measures taken” by him, while the UAE's minister of state for foreign affairs said Trump's decision “is the correct one.”
Bijan Sabbagh and Karen DeYoung contributed to this report.