Usually it's the president or some senior State Department representative that throws around threats against a foreign nation. However, this week the Pentagon skipped right past the executive branch and threatened Iran directly.

The Pentagon issued a rare public warning to Iran on Wednesday against a potential transfer of hundreds of unmanned drones to Russia for use in the Kremlin’s war against Ukraine.

“We would advise Iran not to do that,” US Defense Secretary Lloyd Austin told reporters at the Pentagon today. “We think it’s a really, really bad idea. And I’ll leave it at that.”
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US officials say Moscow has used up much of its precision-guided missile stockpile since its Feb. 24 invasion of Ukraine, which has bogged down amid intense Ukrainian resistance and flows of heavy weapons from US and its Western allies.
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Neither Austin nor Milley specified what steps the US might take if Iran does transfer the drones to Russia, though the Pentagon typically has a variety of options, both overt and covert, for White House officials to choose from. Any such response would be a matter for US policymakers, Milley suggested today.

No, it wouldn't be up to US policymakers, because the Pentagon, the standing army of the United States, is directly threatening a foreign nation for selling arms to a third-party that we are not at war with. That sound very Late-Roman-Empirish.
It doesn't sound like something a democracy would do.
Top Air Force General, Lt. Gen. Alexus Grynkewich, also used this arms sale, as well as China's successful economic contacts to say, “Something will occur that unleashes that planning and that preparation against us.”

These weren't the only threats being thrown around. Our NATO ally Turkey had a warning to give.

"The US needs to leave the areas on the east of the river Euphrates, this is our conclusion at the Astana [talks]," Erdogan told a group of journalists who accompanied him to Tehran on Tuesday for a trilateral summit with his Iranian and Russian counterparts.
"It is the US that feeds the terror groups there; it would ease our work if the US withdraws or cuts support to these groups."...
The operation, if it goes forward, will be the fourth of its kind mounted by Ankara in northern Syria since 2016, and will be conducted with the declared purpose of combatting threats to Turkey from the Islamic State (IS) group and PKK-allied Syrian Kurdish groups, as well as enabling the resettlement of internally displaced Syrians.

Erdogan said Iran and Russia were in agreement against the PKK and YPG, and the group was also hurting the Syrian government.

“This terror group is sucking the oil wells in the east of the river Euphrates, they exploit them and then sell them to the regime,” Erdogan said, adding that the US was still aiding and abetting the Syrian Kurdish groups.

He added that US officers were still training the YPG militants while they raise the Syrian government flags. “They believe that they can trick the Turkish military by waving the Syrian government flag as they attempt terrorist acts against the Turkish soldiers,” he said.

If Turkey invades our Kurdish allies have said that they will switch to backing the Syrian government. At which point we'll have 900 soldiers behind enemy lines.
The U.S. has only said that it's "monitoring the situation."