Iran army 'prepared' to take on 'cruel, criminal' US
The comment comes as the two countries continue to trade threats and insults after the US withdrew from the nuclear deal.
"Iranian armed forces are now, thanks to God, more prepared than ever and will not wait for the permission or approval of any power to develop defence capabilities," Major General Mohammad Bagheri said, according to state news agency IRNA.
The statement follows a warning issued by US Secretary of State Mike Pompeo that Washington will apply "unprecedented financial pressure" on Iran with the "strongest sanctions in history" if Tehran did not scale down its regional influence and curb its missile programme.
Iran's Revolutionary Guard also rebuffed Pompeo's threats.
"The people of Iran should stand united in the face of this and they will deliver a strong punch to the mouth of the American Secretary of State and anyone who backs them," a commander from the group said.
President Donald Trump announced on 8 May that the US would wihdraw from a landmark multi-state agreement from 2015 that saw sanctions lifted on Iran in exchange for curbing its nuclear weapons programme.
The withdrawal has been seen as a major risk to the stability of the region and impetus for Iran to expedite its nuclear programme and widen its influence in regional conflicts, such as in Syria.