Are any of the Iranians in the prisoner swap a threat to national security?

In announcing a surprise prisoner swap alongside Iran’s fulfillment of its nuclear deal obligations, the Obama administration portrayed the 21 Iranians who were in effect pardoned as little more than sanctions-busters, emphasizing they had not been charged with violent or terrorism-related crimes.

But many in the group were assisting Iran’s military, spy services and nuclear program, providing what one U.S. attorney called a threat to national security. At least two suspects reportedly lent logistical support to what the United States considers a terrorist group.

Seven of the 21 were pardoned or had their sentences commuted as part of the trade for four Americans imprisoned in Iran. The other 14 were fugitives, believed to be overseas, and arrest warrants were dropped against them.

Among the 14 were Hamid Arabnejad and Gholamreza Mahmoudi, senior executives with Iran’s Mahan airline. U.S. officials say the airline ran supplies to Hezbollah, the Lebanese-based Islamic organization that the U.S. considers a terrorist group.

The airline also is accused of providing logistics support, including covert travel, to the Quds Force, the elite overseas unit of the hard-line Revolutionary Guard. The U.S. has designated the Quds Force a supporter of terrorism since 2007.

Arabnejad was separately accused of using Mahan to smuggle weapons to Syrian President Bashar Assad for the “regime’s violent crackdown against its own citizens,” according to a 3-year-old Department of Treasury designation that imposes sanctions.

In the prisoner swap, Tehran agreed to free four Americans who had dual U.S.-Iranian citizenship, including Washington Post reporter Jason Rezaian, after long ordeals in Iranian prisons. Iran separately released a fifth American, a student who had spent about 40 days in jail.

In exchange, the United States freed six U.S.-Iranian dual nationals plus a seventh Iranian citizen, Nima Golestaneh, from U.S. prisons.

The seven all chose to stay in the U.S. after their release, although Golestaneh’s immigration status is unclear. He was extradited from Turkey in February and pleaded guilty to hacking a Vermont aerodynamics company and defense contractor to steal software.

Three of the seven — Khosrow Afghahi of Los Angeles, and Tooraj Faridi and Bahram Mechanic, both of Houston — were part of the same case. They are accused of shipping to Iran an estimated 28 million electronic parts valued at $24 million between July 2010 and April 2015, according to federal court documents in Houston.

Prosecutors said the three violated U.S. export laws, used intermediaries in Taiwan and Turkey to conceal the illicit shipments, and shipped specialized circuits and microprocessors used in the guidance systems of cruise missiles and surface-to-air missiles.

The three pleaded not guilty and were awaiting trials. They received pardons as part of the deal.

Arash Ghahreman, another of the seven, had his 6 1/2-year prison sentence commuted. He was convicted in federal court in San Diego last summer for his role in a scheme to send fiber-optic gyrocompasses and electron tubes, which have both civilian and military uses, to Iran through a front company in Dubai, United Arab Emirates.

“The proliferation of sensitive U.S. technologies to Iran continues to be a threat to U.S. national security,” U.S. Atty. Laura Duffy, who handled the case, said at the time.

Ellis M. Johnston III, Ghahreman’s lawyer in San Diego, said the gyrocompasses and other items were for commercial use. He said Ghahreman, who lives in Staten Island, N.Y., was relieved after his release and planned to spend time with his family.

“He just wants to have some privacy and figure out what happened over the last 72 hours,” Johnston said Tuesday.

Another prisoner who had his sentence commuted, Nader Modanlo, was sentenced to eight years in prison in 2013 for his role in helping Iran launch a spy satellite in 2005. The $10-million fee he forfeited for conspiring to provide illegal satellite services to Iran will not be returned.

Ali Saboonchi, of Parkville, Md., was convicted in 2014 of illegally exporting American-manufactured industrial products to Iran, including “cyclone separators” used in petroleum refineries, and specialty filters used in nuclear plants and the oil and gas industry. His sentence was commuted.

Among the 14 accused was Seyed Abolfazl Shahab Jamili, an Iranian businessman who was charged in absentia in 2013 with violating U.S. export laws by conspiring to buy specialized sensors called “pressure transducers” that can be used in gas centrifuges to enrich uranium. The Justice Department dismissed 10 criminal counts against Jamili on Saturday.

“The government is dismissing the counts against defendant Jamili based upon issues regarding securing extradition of the defendant and significant foreign policy interests,” said the U.S. attorney for the district of Massachusetts, Carmen M. Ortiz.

Some of the Iranians who were freed or who are not going to be pursued could still be prosecuted on other sanctions violations since the U.S. trade embargo against Iran remains in place. So do specific sanctions for Iran’s human rights abuses, support of terrorism and, most recently, its ballistic missile program.

For the prisoner exchange, Iran initially submitted a long list to U.S. negotiators of Iranians and Iranian Americans in U.S. custody.

Atty. Gen. Loretta Lynch rejected “several dozen” names from the list, said a U.S. official who spoke on condition of anonymity in discussing the process. Lynch was concerned about setting a precedent if individuals charged with terrorism or violent crimes were released.

During secret talks that stretched over 14 months at the margins of the nuclear negotiations, the American side refused to characterize the exchange as a “spy swap,” which further complicated the criteria. The Iranian government considered Rezaian and the other Iranian Americans it was holding to be spies; the U.S. did not.

Instead, the U.S. insisted that the releases be considered “humanitarian gestures,” the U.S. official said.

As the hour of the swap neared last weekend, complications at both ends nearly derailed the exchange.

One Iranian serving time in a U.S. prison initially refused to participate. He was nearing the end of his sentence and felt he might win an appeal. He eventually was persuaded to accept his release.

In Tehran, the jet preparing to take Rezaian and the two other prisoners to freedom was delayed when Rezaian’s wife, Yeganeh Salehi, and his mother, Mary, could not be found. Salehi, an Iranian journalist, was on an Iranian “no fly” list, U.S. officials were told, and would not be allowed to board the aircraft.

Diplomats scrambled to find the two and resolve the issue. In the meantime, members of the Swiss flight crew reached their maximum hours on duty and had to take a required rest. The three freed prisoners and Rezaian’s wife and mother were eventually allowed to board the Swiss plane and depart.

The delays in Tehran also pushed back by several hours the release of the prisoners in the U.S., which had to be coordinated with several prisons across the country and timed with the departure of the Americans from Tehran.

Times staff writer Molly Hennessy-Fiske in Houston contributed to this report.