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.