Iran's supreme leader has challenged US president Donald Trump over America pulling out of the nuclear deal, saying: "You cannot do a damn thing."

Ayatollah Ali Khamenei's comments came as he met a group of school teachers in Tehran, a day after Mr Trump announced he was renewing sanctions on Iran.

Khamenei described Mr Trump's speech on Tuesday night as having "over 10 lies".

He also said Mr Trump's remarks threatened Iran's people and its theocratic government.

Under Iran's Islamic Republic, Khamenei has the final say on all state matters.

The exhortation from Khamenei follows a pattern of Iranian leaders declaring their nation's ability to resist foreign pressure or interference.

Meanwhile, Iranian legislators set fire to a US flag inside parliament, shouting: "Death to America!"

The government backlash reflected public anger in Iran over Mr Trump's decision, which threatens to destroy the landmark 2015 agreement. Iranian officials, including the parliament's speaker, have said they hope Europe will work with them to preserve the deal, but many are pessimistic.

MPs, including a Shia cleric, held the flaming flag alight as their colleagues joined their chants. They also burned a piece of paper representing the nuclear deal and stomped on the papers' ashes.

While US flag-burning is common in Iran and harsh criticism of America has been a staple of Iranian parliamentary politics for years, it was the first time political observers could remember anything being burned inside the parliament itself.

The 2015 agreement imposed restrictions on Iran's nuclear programme in return for the lifting of most US and international sanctions.

However, the deal came with time limits and did not address Iran's ballistic missile initiative or its regional policies in Syria and elsewhere.

Mr Trump has repeatedly pointed to those omissions in referring to the accord as the "worst deal ever". Proponents of the deal have said those time limits were meant to encourage more discussion with Iran in the future that could eventually address other concerns.

On Tuesday night, Iranian president Hassan Rouhani said he would send foreign minister Mohammad Javad Zarif to the countries still in the deal - China, France, Germany, Russia and the United Kingdom.

Iran hopes the European Union will pass laws to protect European firms from any potential US sanctions. EU officials have suggested they will do what they can to salvage the agreement.

Mr Rouhani also made a point of stressing that Iran, at any time, could resume its nuclear programme.

"So if necessary, we can begin our industrial enrichment without any limitations," the Iranian leader said.

"Until implementation of this decision, we will wait for some weeks and will talk with our friends and allies and other signatories of the nuclear deal, who signed it and who will remain loyal to it. Everything depends on our national interests."

On Wednesday morning, parliament speaker Ali Larijani said responsibility for saving the deal fell on the EU and other world powers still in the accord.

He said: "The period is only a window in which the EU can prove if it has enough weight for settling down international issues or not."

Mr Larijani also urged the country's nuclear department to prepare for "resumption of all aspects of nuclear activities"

The Iranian rial is already trading on the black market at 66,000 to the dollar, despite a government-set rate of 42,000 rials. Many Iranians say they have not seen any benefits from the nuclear deal.

The country's poor economy and unemployment levels sparked nationwide protests in December and January that saw at least 25 people killed and, reportedly, nearly 5,000 arrested.