Iran said on Monday that it arrested 17 suspects and sentenced some to death after allegedly dismantling a CIA spy ring.
Security agencies "successfully dismantled a (CIA) spy network," the head of counter-intelligence at the Iranian intelligence ministry, whose identity was not revealed, told reporters in Tehran.
"Those who deliberately betrayed the country were handed to the judiciary... some were sentenced to death and some to long-term imprisonment."
The suspects were reportedly arrested between March 2018 and March 2019.
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.
Iran’s new claims come amid soaring tensions between Tehran and Washington.
In May 2018, President Donald Trump unilaterally withdrew the US from a landmark 2015 deal putting curbs on Iran's nuclear program in exchange for sanctions relief.
The US administration reimposed biting sanctions on Iran, which retaliated by increasing its enrichment of uranium beyond limits set in the nuclear accord.
Trump called off air strikes against Iran at the last minute in June after Iran downed a US drone, one of a string of incidents including attacks on tankers in the Gulf.
The tensions have escalated since British authorities seized an Iranian oil tanker on suspicions it was shipping oil to Syria in breach of EU sanctions.
In what was seen by Britain as a tit-for-tat move, Iran's Revolutionary Guards seized a UK-flagged tanker in the strategic Strait of Hormuz on Friday, angering the US ally.