You cannot wage economic war against the Islamic Republic without paying a price.
US officials believe that was the message delivered by two explosions on two oil tankers in the Gulf of Oman.
Since pulling the US out of the Iranian nuclear deal in 2015, Donald Trump's Administration has pursued a "maximum pressure" economic sanctions policy against Iran in a bid to force it to accept more intrusive restrictions on its nuclear activities.
President Hassan Rouhani and his Foreign Minister Javad Zarif have been working to in their words "save" the deal they championed.
Ultimate power in Iran lies with Supreme Leader Ayatollah Ali Khamenei. He can fire presidents and ministers, veto laws and directs foreign and security policy. He is the real commander in chief.
If he had ordered a sabotage operation, Rouhani and Zarif would have been powerless to stop it. There is a good chance they would not even have known about it. Planting mines on tankers is a risky but effective way to play havoc with global oil supplies without an all-out war.
But if the Iranian regime believes such threats will force the Trump Administration to change course, they are likely to be disappointed. Hawks in Washington are likely to conclude that Iran is lashing out because it is under pressure — and that if they push ahead with their pressure, Iran will buckle. They, too, are likely to be disappointed. The Islamic Republic has been under siege in one form or another for most of its existence. Resistance is in the regime's DNA.
With neither side likely to back down, the Gulf of Oman is likely to become increasingly dangerous.
Q&A
What is at stake?
Almost a fifth of the world's oil is shipped through the 33km-wide Strait of Hormuz.
What could happen?
Shipping insiders said tanker firms may be forced on to a "conflict footing".
Has this happened before?
The spate of alleged Iranian attacks on oil ships in the Gulf of Oman has raised global fears of a return to the "Tanker Wars" of the 1980s when US warships fought cat-and-mouse battles with Iranian forces to protect tankers.