Iranian Vice President Masumeh Ebtekar told BBC that while Tehran had the right to defend itself, it had no intention of dominating the region.
Ebtekar hoped to regain the trust of neighbouring states and co-operate with them to counter extremist groups in the region, BBC reported on Tuesday.
Iran has long been accused of fomenting unrest throughout the Middle East, providing assistance to Syrian President Bashar al-Assad and the Lebanese militant Islamist group Hezbollah, and allegedly backing Yemen's rebel Zaidi Shia Houthi movement.
Ebtekar said the recent deal where Iran agreed to limit its sensitive nuclear activities in return for the end of crippling sanctions represented a "step forward" for the whole world.
"It means a new era of working with the world in terms of different dimensions of trade, cultural exchanges," she explained. "It means that Iran is going to be a more prominent player in this part of the world."
The vice-president insisted that Iran would not stop supporting those "threatened by the policies of the Zionist regime", meaning Israel, and needed to be able to defend itself in a region where there were so many US military bases.
But, she added, Iran also wanted to use its influence "to promote peace and stability". "Our foreign minister is travelling in the region, because maintaining ties, actually restoring trust with our neighbours is an issue for us."
"We hope to be able to restore that trust working with different regional states to be able to stand firm against extremism, against terrorism, against IS which is a terrible phenomenon," she added.
She said Iran had been "trying to establish a dialogue" through diplomatic channels with regional Sunni power Saudi Arabia, which is leading an international coalition trying to drive back the Houthi rebels in Yemen and restore the country's exiled president.
"We have to resolve the war in Yemen which is devastating that nation."