Iran's supreme leader Ayatollah Ali Khamenei said Tehran has neutralised US plans in the Middle East, in a speech Wednesday marking the Persian New Year.
"Those who interfere in all the affairs of the world protest and ask: 'Why does Iran intervene in the affairs of Iraq and Syria?' What is it to you? The Islamic Republic of Iran has succeeded in neutralising US plans in the region," he said.
Khamenei accused the United States of planning to "create oppressive and rebel groups like Daesh (the Islamic State group) to distract people in the region from the Zionist regime (Israel) and keep them occupied with internal conflicts".
The all-powerful Iranian leader's speech was delivered in the holy city of Masshad and broadcast on state television.
Iran has supported the governments of Syria and Iraq by sending "military advisers" and its own "volunteers" along with Afghans and Pakistanis to fight jihadists and rebels.
Its presence in the region has been denounced by the United States as well as France, Britain, Saudi Arabia and Israel.
Khamenei said Iran was there "at the request of the governments and people" of those countries.
"Without a doubt, the United States will not reach its goals in the region and, thank God, we will achieve ours," he added.
His comments came after US President Donald Trump angered Iran over a message to its people on the occasion of the Nowruz New Year celebrations.
In the message, Trump said: "The Iranian people face another challenge: rulers who serve themselves instead of serving their people".
Iran's foreign minister, Mohammad Javad Zarif, on Tuesday lashed out at the "absurd insults".
© 2018 AFP