Who are the US citizens still being held abroad?

Reporter Evan Gershkovich, former US Marine Paul Wheelan and journalist Alsu Kurmasheva are in the US now, freed from captivity in Russia as part of a historic prisoner swap earlier this week.

But even as the US government celebrates their return, dozens of Americans are currently being held hostage or wrongfully detained in 16 countries across the world.

Data from the James W Foley Legacy Foundation - named after a journalist kidnapped and killed in Syria - suggests that more than 40 Americans are unjustly held abroad, many of them for years after sham trials.

Majority of the cases mentioned in the report, 78%, involved a wrongful detention by state actors like China, Iran or Russia. The rest are hostage cases by non-state actors including Hamas, which is currently holding at least five American citizens.

But the true figure of those detained abroad is likely higher.

The families of some US detainees have purposely avoided the spotlight, while others have yet to be designated as wrongfully detained by the US.

Here's a few of the cases that we know about:

Among the Americans still being held in Russia are Ksenia Karelina, a 32-year-old amateur ballerina and spa employee based in California.

In February, Russian authorities announced that Ms Karelina - a dual citizen who was visiting family members in the country - was arrested on treason charges.

The charges allegedly stemmed from a $51.89 (£40.43) donation to a New York-based charity that buys gear for Ukrainian emergency workers.

Following the US-Russia prisoner swap, Ms Karelina's boyfriend, Christopher van Heerden, told Reuters that he was disappointed that she was not included in the deal.

"I'm happy for the people, the Americans, who have returned to their families," he said. "This makes me hopeful. At the same time, I'm heartbroken and sad...she's not on the list."

Ms Karelina's trial is expected to begin next week.

While the US government has not commented publicly on the case, Mr van Heerden said they were aware and sought to not "upset" Russian authorities before the trial.

Freelance journalist and former US Marine Austin Tice, 31, was kidnapped in August 2012 while working in Syria.

While no government or group claimed responsibility for his disappearance, US officials soon said they believed that he was being held by the Syrian government - a position they have since maintained.

Syria's government has said it is unaware of Mr Tice's whereabouts.

In 2022, US President Joe Biden met the Tice family and said that the US knew "with certainty" that he was being held by the Syrian government.

In May this year, Mr Biden again mentioned Mr Tice as being "held hostage".

After 12 years, he is now believed to be the longest-held US journalist in history.

Marc Fogel, 63, a teacher at the Anglo-American School of Moscow, was arrested at an airport in August 2021 and charged with carrying a small amount of medical marijuana which had been prescribed in the US.

He is currently serving a 14-year prison sentence and has reportedly been teaching English to fellow inmates.

In the wake of the US-Russia prisoner swap, Ms Fogel's family said in a statement that he was "left behind again".

"Marc has been unjustly detained for far too long and must be prioritised in any swap negotiations with Russia, regardless of his level of notoriety or sobriety," the statement added.

On 1 August, US National Security Advisor Jake Sullivan said that the US was "actively working to get his release".

When asked about the Fogel case the following day, President Biden said that "we're not giving up on that".

Mark Swidan, a Texas businessman and graphic designer, has been imprisoned in China on drug charges since 2012. He denies the charges.

A later United Nations review of the charges found that Mr Swidan - who was in China to buy flooring supplies at the time of his arrest - was not in the country at the time of his alleged crime.

The US government considers him, along with two other Americans, as being wrongfully detained in China.

In April, his mother Katherine Swidan told CBS, the BBC's US partner, that the family was "very concerned and afraid that Mark will end his life".

The family has also alleged that Mr Swidan has undergone torture while in Chinese custody, including having both hands broken and his kneecaps dislocated.

"His leg is so swollen that they may not be able to get the brace off his leg without cutting it off," Ms Swidan said in a February news conference. "He's ill. He's eating only bread."

New York native Ryan Corbett was arrested after returning to Afghanistan in August 2022 after having left the country when the Taliban swept to power the previous year.

He had previously lived in the country for many years, and ran and supervised projects for a number of NGOs.

To date, Mr Corbett has not been charged with a crime. Taliban officials have told CBS that he was involved in "anti-state" activities.

He is among three US citizens the US government believes are being held by the Taliban, who have expressed an interest in freeing them in exchange for Afghan citizens still held by the US.

In March, his family said they received a "disturbing call" from Mr Corbett in Afghanistan in which he "exhibited a significantly deteriorated mental state".

"I want the president to realise that the lack of action to bring Ryan home could have disastrous consequences," his wife Anna told CBS.

While US officials have held several meetings with Taliban representatives to secure his release, they have not disclosed whether any progress has been made.

Several US lawmakers, including New York representative Claudia Tenney, have also publicly called for his release.