Iranian officials are slamming the United States for imposing sanctions on the country's foreign minister, Mohammad Javad Zarif, personally targeting Iran's highest ranking diplomat. The move comes amid rising tensions between the two countries, which have long been at odds.

Zarif took to Twitter to criticize the sanctions in a message laced with sarcasm and incredulity.

"The US' reason for designating me is that I am Iran's 'primary spokesperson around the world' Is the truth really that painful?" Zarif wrote. "It has no effect on me or my family, as I have no property or interests outside of Iran. Thank you for considering me a huge threat to your agenda."

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Iran's President Hassan Rouhani described the move as "childish" and a barrier to diplomacy. "Every day they claim: 'We want to negotiate with Iran, without any pre-conditions,' and then they put sanctions on the country's foreign minister," Rohuani said in a speech Thursday, the Associated Press reported.

Others at the United Nations have voiced their own opinions on the U.S.' latest sanction on Iran. U.N. Secretary General Antonio Guterres took an indirect swipe at the U.S. on the new visa sanctions, saying, "When I ask for maximum restraint, I ask for maximum restraint at all levels."

And, when Russia's Deputy U.N. Ambassador Dmitry Polyanskiy was asked about the new sanctions on Iran's Foreign Minister, he said, "It is very difficult sometimes to get into the heads of the Americans. It remains an enigma. Like a woman's mind sometimes Americans' minds are very mysterious," CBS News' Pamela Falk reports from the U.N.

Secretary of State Mike Pompeo announced the sanctions on Wednesday, describing Zarif as someone "who enriched himself at the expense of the Iranian people." On Twitter, Pompeo posed a picture of Zarif and stated, "Foreign Minister Zarif, a senior regime official and apologist, has for years been complicit in the Iranian regime's malign activities."

Recently, President @realDonaldTrump sanctioned Iran’s Supreme Leader, who enriched himself at the expense of the Iranian people. Today, the U.S. designated his chief apologist @JZarif. He’s just as complicit in the regime’s outlaw behavior as the rest of @khamenei_ir’s mafia. pic.twitter.com/XhDdqR6rik — Secretary Pompeo (@SecPompeo) July 31, 2019

Pompeo has recently given mixed signals regarding policy toward Iran. Earlier this week, Pompeo wrote on Twitter, "I recently offered to travel to Tehran and speak directly to the Iranian people. The regime hasn't accepted my offer." Zarif called his offer "empty and disingenuous."

Tensions between the U.S. and Iran have been on the rise this summer. On June 19, Iran seized a British-flagged oil tanker and also detained an additional vessel in the Strait of Hormuz. Iran's aggressive posture follows President Trump's 2018 decision to withdraw the U.S. from the 2015 nuclear deal between Iran, the United States and other world powers. The Trump administration has also imposed sweeping economic sanctions on Iran, including restricting its oil exports, leaving the economy in shambles.

In June, President Trump nearly engaged in a military strike against Iran, after a U.S. drone was shot down in Iranian airspace. Mr. Trump said the U.S. military was "cocked and loaded" to retaliate against Iran at three different sites on June 21, but he said he called off the operation after learning 150 people would likely be killed.