US Secretary of Defense James Mattis affirmed the indifference of the United States to the threats of Iran following the attack on an Iranian military parade that killed 29 people, including 12 members of the elite Revolutionary Guards.
Mattis stated that it was absurd for Iran to accuse the US of having any connections with this terrorist attack.
He criticized the role of Iran in Syria, stressing that the US military works to defeat ISIS and train local forces.
Supreme Leader of Iran Ali Khamenei has said that there are parties that are in contact with some countries responsible for the terrorist attack that took place in Ahvaz on Saturday.
Khamenei asserted the attack was carried out by parties that are protected by the US and funded by Saudi Arabia and the United Arab Emirates.
Moreover, Rouhani said on Sunday that Iran was ready to confront the United States and its Gulf Arab allies.
Speaking in Tehran before heading to attend the annual UN General Assembly in New York, Rouhani accused US-backed Gulf Arab states of providing financial and military support for anti-government ethnic Arab groups in Iran.
"America is acting like a bully toward the rest of the world...and thinks it can act based on brute force," said Rouhani, who engineered Iran's 2015 nuclear deal that ushered in a cautious detente with Washington before tensions flared anew with President Donald Trump's decision to quit the accord.
"But our people will resist and the government is ready to confront America. We will overcome this situation (sanctions) and America will regret choosing the wrong path."