Iran will not succumb to threats, but it won't hesitate to issue its own. From [1] Iran Focus, with thanks to Mackie:

Tehran, Iran, Aug. 14 – Iran issued a stark warning on Sunday that it would change its nuclear policy for the worse if the West continued to apply pressure on it to abandon uranium enrichment.

“Naturally, if Europe goes down the wrong path, we will definitely change our path and act proportionately”, Foreign Ministry spokesman Hamid-Reza Asefi told reporters during his weekly press conference. His remarks were reported in the state-run news agency ISNA....

“The Islamic Republic will not succumb to the language of fear and threats”, Asefi said.