Iran will defy United States pressure and continue developing missiles and other weapons, President Hassan Rouhani told crowds gathered in Tehran on Monday to mark the 40th anniversary of the Islamic Revolution.
"We have not asked for and will not ask for permission to make missiles. We will continue our military and defensive path," Mr Rouhani said in a nearly 45-minute speech in which he lashed out at the US and Israel.
Faced with crippling sanctions imposed after Washington pulled out of the 2015 Iran nuclear deal last year, Mr Rouhani accused the US of a "conspiracy" against his country that he said would not succeed.
"The presence of people today on the streets all over Islamic Iran ... means that the enemy will never reach its evil objectives," he told the crowd gathered in freezing rain at Tehran's Azadi square.
Militia members in camouflage fatigues and ordinary citizens marched through the capital along a route lined with life-sized replicas of Iranian cruise and ballistic missile in an apparent show of defiance towards the US.
Banners held by marchers or hung along the streets bore slogans including "Death to America", "Death to Israel", "We will trample on America", and "Forty years of challenge, forty years of US defeats".
President Donald Trump pulled the US out of the nuclear deal that lifted economic sanctions on Iran in May last year, saying Tehran was posing an increasing threat to the Middle East region through its missile programme and funding of militant groups. The move sent the Iranian currency plummeting, prompted international companies to pull out of deals in Iran and slashed Tehran's oil exports as buyers halted purchases to avoid punitive US action.
France, Britain and Germany, the other western powers that were signatories to the pact along with China and Russia, stood by the deal and pledged to work around US sanctions to continue trade with Iran.
President Rouhani said Iran was fighting a psychological war with the enemy and needed to stay united to win.
"Iran will not let the US win this war. The US has repeatedly announced in the past few years that Iran would fall but to no avail," he said.
A resolution was read out that called Mr Trump an "idiot" and proclaimed "unquestioning obedience to the supreme leader Ayatollah Ali Khamenei".
Monday's events were the culmination of annual celebrations called the "10 Day Dawn" that mark the period between February 1, 1979 and February 11 when Shiite cleric Ayatollah Ruhollah Khomeini returned from exile and ousted the government of Iran's last shah.
Fireworks displays were held across Tehran on Sunday night as supporters of the revolution shouted chants of "Allahu Akbar" from rooftops, recalling the protests that swept Khomeini to power four decades earlier.
Mr Khamenei, who succeeded Khomenei in 1989, is set to publish "a detailed statement explaining the 'second step' of the progress of the Islamic revolution", his official website said.
