"Iran answers diplomacy with diplomacy and pressure with resistance," Mousavi said on Saturday night.
He was reacting to comments by US National Security Council Spokesman Garrett Marquis who has reiterated that "Iran should answer diplomacy with diplomacy", urging Iran to quit its nuclear program.
However, he added, it appears that in the lexicon of American authorities, diplomacy means sanctions and economic terrorism.
"Thus far we have not seen anything other than illegal sanctions and economic war and terrorism from the US government to respond," he noted.
Last Friday, Mousavi reminded US Special Representative for Iran Brian Hook that Washington's economic terrorism, warmongering and threats against Tehran deserve reciprocal measures, not diplomacy and respect, adding that his country surely defends itself when it comes under attack by the White House.
In his last week tweet, Mousavi said Iranians will respond diplomacy with diplomacy, respect with respect and war with defense.
Referring to the US Special Representative for Iran and Senior Policy Advisor to Secretary of State Mike Pompeo, Brian Hook, Abbas Mousavi wrote on his Twitter account, "Mr. Hook! Do you call imposed war and economic terrorism against Iranian nation and violation of commitments and resolutions diplomacy?"
Earlier, Hook had urged Iran to respond Washington's diplomacy with diplomatic approach and to avoid military acts.