"Economic experts and many officials believe the cause of this issue is not foreign, it's internal," he said in a speech in Tehran, according to tweets released on his official account.
"Not that sanctions don't have an impact, but the main factor is how we handle them."
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He referred specifically to the collapse in the currency, which has lost around half its value since April.
"If our performance is better, more prudent, timely and effective, sanctions will not have that much effect and can be resisted," he added.
The speech was not immediately televised. They are usually broadcast later in the day.
There have been widespread protests and strikes in recent weeks over high prices, unemployment and the wider management of the economy.
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Analysts say US hostility, including its withdrawal from the 2015 nuclear deal and reimposition of sanctions, helped fuel the run on Iran's rial. But many say it has only exacerbated long-standing problems within
Iran - and pressure has mounted from within the system on President Hassan Rouhani to improve his management of the economy and tackle corruption.
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