Iran is not too happy with President Donald Trump’s speech at the UN this morning, and its top diplomat didn’t have a particularly diplomatic response.

“Trump's ignorant hate speech belongs in medieval times-not the 21st Century UN -unworthy of a reply,” tweeted Javad Zarif, Iran’s foreign minister. “Fake empathy for Iranians fools no one.”

Zarif was responding to Trump’s repeated attacks on Iran during his high-profile speech in New York, which used rhetoric that was harsh even by his own standards.

“The Iranian government masks a corrupt dictatorship behind the false guise of a democracy,” Trump said. “It has turned a wealthy country with a rich history and culture into an economically depleted rogue state whose chief exports are violence, bloodshed, and chaos.”

The animosity between the two countries comes at a bad time. On October 15, Trump will decide whether the US will stay in the Iran nuclear deal, an agreement between the US, Iran, and European and Asian powers that lifted a series of punishing economic sanctions in exchange for Tehran accepting strict curbs on its nuclear-related activities. The punishment for Iranian cheating — like operating prohibited technology used to produce nuclear material — is the reimposition of sanctions.

In his speech, Trump called the Iran deal “an embarrassment to the United States.”

“Frankly, that deal is an embarrassment to the United States, and I don't think you've heard the last of it. Believe me,” Trump said, perhaps alluding to his decision next month.

But nothing shows just how upset Trump’s remarks made Iranian officials than the scowl by Tehran’s representative as he watched the speech (see below).

It’s safe to say tensions between the two countries won’t go away any time soon.

Read the Iran portion of Trump’s UN speech below:

The Iranian government masks a corrupt dictatorship behind the false guise of a democracy. It has turned a wealthy country, with a rich history and culture, into an economically depleted rogue state whose chief exports are violence, bloodshed, and chaos. The longest-suffering victims of Iran's leaders are, in fact, its own people. Rather than use its resources to improve Iranian lives, its oil profits go to fund Hezbollah and other terrorists that kill innocent Muslims and attack their peaceful Arab and Israeli neighbors.

This wealth, which rightly belongs to Iran's people, also goes to shore up Bashar al-Assad's dictatorship, fuel Yemen's civil war, and undermine peace throughout the entire Middle East. We cannot let a murderous regime continue these destabilizing activities while building dangerous missiles, and we cannot abide by an agreement if it provides cover for the eventual construction of a nuclear program. The Iran deal was one of the worst and most one-sided transactions the United States has ever entered into. Frankly, that deal is an embarrassment to the United States, and I don't think you've heard the last of it. Believe me.

It is time for the entire world to join us in demanding that Iran's government end its pursuit of death and destruction. It is time for the regime to free all Americans and citizens of other nations that they have unjustly detained. Above all, Iran's government must stop supporting terrorists, begin serving its own people, and respect the sovereign rights of its neighbors. The entire world understands that the good people of Iran want change, and, other than the vast military power of the United States, that Iran's people are what their leaders fear the most. This is what causes the regime to restrict internet access, tear down satellite dishes, shoot unarmed student protesters, and imprison political reformers.

Oppressive regimes cannot endure forever, and the day will come when the people will face a choice. Will they continue down the path of poverty, bloodshed, and terror, or will the Iranian people return to the nation's proud roots as a center of civilization, culture, and wealth, where their people can be happy and prosperous once again? The Iranian regime's support for terror is in stark contrast to the recent commitments of many of its neighbors to fight terrorism and halt its finance, and in Saudi Arabia early last year, I was greatly honored to address the leaders of more than 50 Arab and Muslim nations. We agreed that all responsible nations must work together to confront terrorists and the Islamic extremism that inspires them.