TEHRAN — Iran’s intelligence operatives have arrested two, and possibly three, Iranians with British connections in the past two months, human rights activists and others said Thursday.
At least two of the three Iranians in question are also British citizens, and the arrests may be part of an attempt by the Iranian authorities to gain leverage in an old dispute with Britain over more than $400 million in undelivered weaponry.
Aras Amiri, a 32-year-old art student and an employee of the British Council, a cultural organization governed by royal charter that promotes Britain abroad, is the latest known to have been arrested.
Ms. Amiri, an Iranian citizen who has lived in Britain for about 10 years and traveled to Iran at least three times a year, has been in custody in Iran since March 14, a cousin in the United States, Mohsen Omrani, confirmed on Thursday.
While some members of her family in Iran sought to keep the arrest quiet, Mr. Omrani said in a telephone interview, he had decided to publicize it, beginning with a Twitter post on Tuesday.
Mr. Omrani said that while he understood the family’s concerns about angering the authorities by publicizing arrests, “what has been proven again and again is that the ones that don’t have any media coverage slip through the cracks.”
The Center for Human Rights in Iran, a New York-based advocacy group, said in a posting on its website that Ms. Amiri has been incarcerated in a wing of Tehran’s Evin Prison operated by the Intelligence Ministry, which is “holding her without access to a lawyer on national security charges.”
Without identifying Ms. Amiri by name, the British Council said, “We are aware that one of our staff has been detained in Iran while making a private family visit.”
The British Council also denied that she had traveled to Iran on its behalf. “This colleague does not travel to Iran for work,” it said in its mailed statement. “She works in the U.K. to support and showcase the Iranian contemporary art scene.”
At least one other Iranian with British connections arrested recently is a dual citizen of Britain and Iran. Abbas Edalat, an academic and antiwar activist, was arrested in mid-April, an Iranian judicial official confirmed last week. Mr. Edalat, a professor of computer science and mathematics at the Imperial College of London, had been invited to speak at an academic event in Tehran.
The fate of another British-Iranian dual citizen, Mahan Abedin, is somewhat murkier. A writer and analyst generally favorable to the Iranian government, Mr. Abedin failed to return as scheduled on April 29 from a visit with family in Iran, said his publisher, Michael Hurst. His only contact with Mr. Abedin, he said, has been a brief note saying he was “fine” and to “please stop contacting me.”
Iran Wire, a news website run by expatriate Iranian journalists, said on Monday that Mr. Abedin had been arrested on suspicion he conspired in an “infiltration” operation. Britain’s Foreign Office disputed that account.
“We have been in contact with the family and they have confirmed that he is not currently in detention,” the office said Thursday in a statement.
Iran’s motivations in such arrests are not always clear, but analysts generally tie them to policy disputes with the countries involved. Iran is currently holding about 30 dual citizens, among them at least five Iranian-Americans whose fate could be tied to President Trump’s self-imposed May 12 deadline to decide whether to scrap the 2015 nuclear agreement.
Iran and the United States negotiated a mutual release of prisoners after the nuclear deal took effect in January 2016.
Iran’s foreign minister, Mohammad Javad Zarif, said in April that Iran was open to prisoner talks, “If the United States changes its attitude.”
At least two dual citizens of Britain and Iran have been imprisoned by the Iranian authorities on vaguely defined charges of espionage. Kamal Foroughi, a business consultant, has been held since 2011 and Nazanin Zaghari-Ratcliffe, a researcher for the Thomson Reuters Foundation charity, has been detained since 2016.
Speculation has grown in recent months that freedom for the Iranians with British connections may be tied to a longstanding legal dispute between Britain and Iran over Iran’s 1976 purchase of British tanks that were never delivered. Britain has said that it owes Iran up to 300 million pounds, a little over $400 million at current exchange rates, but that the precise sum has not been negotiated.
A similar financial dispute over an old arms deal between Iran and the United States appeared to play a role in the 2016 release of Americans held by the Iranians, with the delivery of $400 million to Iran on the same day the nuclear deal took effect.
Thomas Erdbrink reported from Tehran, and Rick Gladstone from New York.