GUWAHATI, India — Shona Banu still shudders when she thinks of the past few days.

The 58-year-old, a resident of Barpeta district in India's north-eastern state of Assam, says that she was called to the local police station on 25 May and later taken to a point at the border with neighboring Bangladesh. From there, she says, she and around 13 other people were forced to cross over to Bangladesh.

She says she was not told why. But it was a scenario she had been dreading — Ms Banu says she has lived in Assam all her life but for the past few years, she has been desperately trying to prove that she is an Indian citizen and not an "illegal immigrant" from Bangladesh.

"They pushed me over at gunpoint. I spent two days without food or water in the middle of a field in knee-deep water teeming with mosquitoes and leeches," Ms Banu said, wiping away tears. After those two days in no man's land — between India and Bangladesh — she says she was taken to what appeared to be an old prison on the Bangladeshi side.

After two days there, she and a few others — she is not sure if all of them were from the same group sent with her — were escorted by Bangladeshi officials across the border, where Indian officials allegedly met them and sent them home.

It's not clear why Ms Banu was abruptly sent to Bangladesh and then brought back. But her case is among a spate of recent instances where officials in Assam have rounded up people declared foreigners by tribunals in the past — on suspicion of being "illegal Bangladeshis" — and sent them across the border. The BBC found at least six cases where people said their family members had been picked up, taken to border towns and just "pushed across".

Officials from India's Border Security Force, the Assam police and the state government did not respond to questions from the BBC.

Crackdowns on alleged illegal immigrants from Bangladesh are not new in India — the countries are divided by a 4,096km (2,545 miles) long porous border which can make it relatively easy to cross over, even though many of the sensitive areas are heavily guarded.

But it's still rare, lawyers working on these cases say, for people to be picked up from their homes abruptly and forced into another country without due process. These efforts seem to have intensified over the past few weeks.

The Indian government has not officially said how many people were sent across in the latest exercise. But top sources in the Bangladesh administration claim that India "illegally pushed in" more than 1,200 people into the country in May alone, not just from Assam but also other states. Out of this, they said on condition of anonymity, Bangladesh identified 100 people as Indian citizens and sent them back.

In a statement, the Border Guard Bangladesh said it had increased patrolling along the border to curb these attempts.

India has not commented on these allegations.

While media reports indicate that the recent crackdown includes Rohingya Muslims living in other states too, the situation is particularly tense and complex in Assam, where issues of citizenship and ethnic identity have long dominated politics.

The state, which shares a nearly 300km-long border with Muslim-majority Bangladesh, has seen waves of migration from the neighbouring country as people moved in search of opportunities or fled religious persecution.

This has sparked the anxieties of Assamese people, many of whom fear this is bringing in demographic change and taking away resources from locals.

The Bharatiya Janata Party — in power in Assam and nationally — has repeatedly promised to end the problem of illegal immigration, making the state's National Register of Citizens (NRC) a priority in recent years.

The register is a list of people who can prove they came to Assam by 24 March 1971, the day before neighbouring Bangladesh declared independence from Pakistan. The list went through several iterations, with people whose names were missing given chances to prove their Indian citizenship by showing official documents to quasi-judicial forums called Foreigners Tribunals.

After a chaotic process, the final draft published in 2019 excluded nearly two million residents of Assam — many of them were put in detention camps while others have appealed in higher courts against their exclusion.

Ms Banu said her case is pending in the Supreme Court but that authorities still forced her to leave.

The BBC heard similar stories from at least six others in Assam — all Muslims — who say their family members were sent to Bangladesh around the same time as Ms Banu, despite having the necessary documents and living in India for generations. At least four of them have now come back home, with no answers still about why they were picked up.

A third of Assam's 32 million residents are Muslims and many of them are descendants of immigrants who settled there during British rule.

Maleka Khatun, a 67-year-old from Assam's Barpeta who is still in Bangladesh, says she has temporarily been given shelter by a local family.

"I have no-one here," she laments. Her family has managed to speak to her but don't know if and when she can return. She lost her case in the foreigners' tribunal and in the state's high court and hadn't appealed in the Supreme Court.

Days after the recent round of action began, Chief Minister Himanta Biswa Sarma cited a February Supreme Court direction which ordered the government to start deportation proceedings for people who had been "declared foreigners" but were still held in detention centres.

"The people who are declared foreigners but haven't even appealed in court, we are pushing them back," Sarma said. He also claimed that people with pending court appeals were not being "troubled".

But Abdur Razzaque Bhuyan, a lawyer working on many citizenship cases in Assam, alleged that in many of the recent instances, due process — which would, among other things, require India and Bangladesh to cooperate on the action — was not followed.

"What is happening is a wilful and deliberate misinterpretation of the court order," he said.

Bhuyan recently filed a petition on behalf of a student organization seeking the Supreme Court's intervention in stopping what they said was a "forceful and illegal pushback policy" but was asked to first approach the Assam high court.

In Morigaon, around 167km from Barpeta, Rita Khatun sat near a table which had a pile of papers on it.

Her husband Khairul Islam, a 51-year-old school teacher, was in the same group as Ms Banu that was allegedly picked up by authorities.

A tribunal had declared him a foreigner in 2016, after which he spent two years in a detention center before being released. Like Ms Banu, his case is also being heard in the Supreme Court.

"Every document is proof that my husband is Indian," Ms Khatun said, leafing through what she said was Mr Islam's high school graduation certificate and some land records. "But that wasn't enough to prove his nationality to authorities."

She says her husband, his father and grandfather were all born in India.

But on 23 May, she says that policemen arrived at their home and took Mr Islam away without any explanation.

It was only a few days later — when a viral video surfaced of a Bangladeshi journalist interviewing Mr Islam in no man's land — that the family learnt where he was.

Like Ms Banu, Mr Islam has now been sent back to India.

While his family confirmed his return, the police told the BBC they had "no information" about his arrival.

Sanjima Begum says she is sure her father was declared a foreigner due to a case of mistaken identity — he was also taken on the same night as Mr Islam.

"My father's name is Abdul Latif, my grandfather was Abdul Subhan. The notice that came [years ago, from the foreigners' tribunal] said Abdul Latif, son of Shukur Ali. That's not my grandfather, I don't even know him," Ms Begum said, adding that she had all the necessary documents to prove her father's citizenship.

The family has now heard that Mr Latif is back in Assam, but he hasn't reached home yet.

While some of these people are back home now, they fear they might be picked up again abruptly.

"We are not playthings," Ms Begum said.

"These are human beings, you can't toss them around as per your whims." — BBC