Iranian Foreign Minister Javad Zarif tweeted on Thursday, saying that Iran does not seek war, "but will zealously defend our skies, land and waters."
The tweet came in response to US President Donald Trump's threatening post on Twitter, saying that "Iran made a very big mistake!" after the Islamic republic shot down a US military drone on Thursday.
"The US wages #EconomicTerrorism on Iran, has conducted covert action against us and now encroaches on our territory," Zarif wrote. "We don't seek war, but will zealously defend our skies, land and waters. We'll take this new aggression to #UN and show that the US is lying about international waters."

Iran claimed on Thursday that the US drone that was taken down was on a spy mission over its territory. However, the US claimed that the attack was in international air space and was "unprovoked."
Zarif said on Twitter that a U.S. military drone that was shot down by Tehran on Thursday had taken off from the United Arab Emirates."At 00:14 US drone took off from UAE in stealth mode & violated Iranian airspace. It was targeted at 04:05 at the coordinates (25°59'43"N 57°02'25"E) near Kouh-e Mobarak. We've retrieved sections of the US military drone in OUR territorial waters where it was shot down," Mohammad Javad Zarif tweeted.
U.S. President Donald Trump said Iran made "a very big mistake" by shooting down the drone that Tehran said was on a spy mission over its territory, in an incident that has fanned fears of wider military conflict in the Middle East.
This was one out of several attacks in an escalating series of incidents in the Gulf region, including strikes on six oil tankers which Iran denied involvement in.
Reuters contributed to this report.