U.S. President Donald Trump on Tuesday said that sanctions re-imposed on Iran were the "most biting ever" as he warned other countries from doing business with Tehran.

"The Iran sanctions have officially been cast. These are the most biting sanctions ever imposed, and in November they ratchet up to yet another level," he wrote in an early morning tweet.

"Anyone doing business with Iran will NOT be doing business with the United States. I am asking for WORLD PEACE, nothing less."

The sanctions re-imposed on Tuesday -- targeting access to U.S. banknotes and key industries such as cars and carpets -- were unlikely to cause immediate economic turmoil.

Iran's markets were actually relatively buoyant, with the rial strengthening by 20 percent since Sunday after the government relaxed foreign exchange rules and allowed unlimited, tax-free gold and currency imports.

But a second tranche coming into effect on November 5 covering Iran's vital oil sector, could be far more damaging -- even if several key customers such as China, India and Turkey have refused to significantly cut their purchases.

Trump's contempt for the nuclear deal dates back to his time as presidential candidate and on May 8, he made good on a pledge to pull America out of the 2015 Joint Comprehensive Plan of Action (JCPOA) that world powers, including the U.S, struck with Iran.

The agreement placed unprecedented curbs on Iran's nuclear program, subjecting it to a rigorous inspection regime in exchange for billions of dollars in relief from international sanctions.

The unilateral withdrawal came despite other parties to the agreement -- Britain, China, France, Germany, Russia and the European Union -- pleading with Trump not to abandon the pact aimed at blocking Iran from acquiring a nuclear weapon.

Trump's tweet came shortly after the EU and heavyweight members Germany, France, and Britain on Monday expressed "deep" regret and vowed to protect Europeans doing "legitimate" business with Iran.