Iran captured 17 spies working for the U.S. Central Intelligence Agency (CIA) and some have been sentenced to death, Iranian media reported Monday.
Iranian state television published images it said showed the CIA officers who were in touch with the suspected spies.
There was no immediate comment on the Iranian allegations by the CIA.
U.S. Secretary of State Mike Pompeo dismissed Iran's claims later on Monday.
"The Iranian regime has a long history of lying," Pompeo said in an interview on Fox News.
U.S. President Donald Trump said Iran's claims are "totally false."
"The Report of Iran capturing CIA spies is totally false. Zero truth," Trump tweeted.
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"Just more lies and propaganda (like their shot down drone) put out by a Religious Regime that is Badly Failing and has no idea what to do. Their Economy is dead, and will get much worse. Iran is a total mess!" he added.
Iran announced in June that it had broken up an alleged CIA spy ring but it was unclear whether Monday's announcement was linked to the same case.
The announcement comes after three months of spiralling confrontation between Iran and the West that began when new tighter U.S. sanctions took effect in May.
In a statement read on state television, the Ministry of Intelligence said 17 spies were arrested during the Iranian calendar year that ended in March 2019.
"The identified spies were employed in sensitive and vital private sector centres in the economic, nuclear, infrastructure, military and cyber areas... where they collected classified information," read the ministry statement.
In a separate report, the semi-official Fars news agency quoted a Ministry of Intelligence official as saying some of those arrested had been sentenced to death.
An Iranian television documentary aired on Monday purported to show a CIA officer recruiting an Iranian man in the United Arab Emirates.
"Because there are so many intelligence officers in Dubai. It is very dangerous... Iranian intelligence," a woman was shown telling an Iranian in the documentary about alleged CIA spying in Iran which was broadcast on state television.
The woman spoke Persian with an accent which appeared to be American.