Speaking at a ceremony on Thursday, Rouhani also urged neighbouring countries to “drive back Zionism”, saying the US and its ally Israel were the root cause of the region’s problems.
He added that Iran’s armed forces were not a threat against any regional country.
“The region’s nations have lived alongside each other for centuries and never had a problem … If there is a problem, it is caused by others,” Rouhani said.
“If we have a problem in the region today, its roots are either with Zionism or America’s arrogance.”
Flanked by top generals, Rouhani told Iran’s neighbours and countries across the region that its armed forces are “never against you or your national interests” but are “standing against the aggressors”.
“Let us stand together, be together and rid the region of the aggressor’s presence,” he added in the speech broadcast live on state television.
During the ceremony, soldiers marched past a podium where Rouhani and top military commanders were standing, while locally designed and produced fighter jets took part for the first time in an air display.
Iran also unveiled missiles, submarines, armoured vehicles, radars and electronic warfare systems. It also showed off its Russian S-300 missile defence system.
Iranian armed forces were more powerful than ever, said Rouhani, amid rising tensions with the US.
“We seek regional security and stability, countries’ sovereignty and end of terrorism and their activities in this region,” he said.
Iran has two armies, one that operates as a national defensive force, and the Islamic
Revolutionary Guard Corps created after the 1979 revolution to protect the Islamic Republic against both internal and external adversaries.
The US officially designated the Revolutionary Guards as a foreign “terrorist organisation” on Monday, an unprecedented move that was condemned by Iran and created concerns about reprisal attacks on US forces.
Rouhani called the US move against the guards “abhorrent” and said “Insulting the Revolutionary Guards is an insult to all [Iranian] armed forces, and an insult to Iranian great nation.”
Iran’s army has the biggest ground force in Iran and the Revolutionary Guards are in control of a growing arsenal of ballistic missiles.
Parades were cancelled in a few provinces where the armed forces were deployed to help flood-affected people. The flooding, which began on March 19, has killed 76 people, forced more than 220,000 people into emergency shelters, and left aid agencies struggling to cope.
Rouhani said: “I doubt we can find this level of unity between people and armed forces in any other country.”
Iran’s Foreign Minister Mohammad Javad Zarif had accused the US of “economic terrorism”, saying its unilateral sanctions were impeding aid efforts to flood-stricken cities.
Iran has received material aid from neighbouring countries such as Pakistan and Kuwait as well as from Germany, France and Japan.