The Tehran government has announced the arrest of seventeen Iranian citizens caught spying for America's Central Intelligence Agency (CIA). Some of those arrested have already been sentenced to death. It is the third major roll-up of CIA agents in Iran that I have been aware of, the first occurring in 1991 involved 20 American agents. The second episode in 2011 led to the arrest of 30 spies. The earlier arrests reportedly eliminated what were presumed to be the entire networks of American agents operating inside Iran and it is to be presumed that the recent arrests will have the same impact.

The Iranians presented a considerable quantity of evidence, including photos and business cards of US government officials, to back up their claim of American spying but President Trump dismissed the report as "totally false" and "just more lies and propaganda" — while Secretary of State Mike Pompeo said: "I would take with a significant grain of salt any Iranian assertion about actions that they've taken."

Iran's press release on the arrests together with a briefing by an intelligence official supplemented by local media coverage provided some of the details. The seventeen reportedly had "sophisticated training" but those who had sabotage missions did not succeed. Other objectives included "collecting information at the facilities they worked at, carrying out technical and intelligence activities and transferring and installing monitoring devices."

Some of the agents had reportedly been recruited by falling into what is referred to as a "visa trap" set by the CIA for Iranians seeking to travel to the US. This has long been the preferred tool for recruiting Iranian agents. The intelligence official handed out a CD with a video recording of an alleged CIA case officer speaking to an Iranian target, which was presumably recorded secretly. The video shows a blonde woman who speaks Persian with an American accent. The disc also included names of several US embassy staff in Dubai, Turkey, India, Zimbabwe and Austria who Iran claims were involved in the recruitment and training of the Iranian spies.

How exactly did the recruitments take place as there is no US Embassy in Tehran and few Americans resident in the country? Many of the Iranians were targeted when they walked into an American Embassy in a country to which they are free to travel, which includes Turkey and Dubai. In the words of the Iranian intelligence official, "Some were approached when they were applying for a visa, while others had visas from before and were pressured by the CIA in order to renew them."

Others were targeted and recruited as spies while attending scientific conferences around the world. Those recruited received promises of money, eventual resettlement and a job in the US or medical assistance. To maintain contact with its agents inside Iran, the CIA would reportedly conceal spyware and instructions in containers that look like rocks, which would be planted in city parks or in rural areas. The Iranian agents would then recover the material, which might include false identification documents. It should be observed that fake rocks are a standard espionage tool. They are hollowed out to conceal spy-gear and communications. After they are in place, a signal is made to alert the agent that there is something ready to be picked-up. In the trade they are referred to as "dead drops."