India has made a diplomatic protest to the US after 129 Indian students were arrested for enrolling in a fake university.
The University of Farmington, advertised as based in Michigan state, was run by undercover agents from the Department of Homeland Security to expose "pay-to-stay" immigration fraud.
Prosecutors say those who enrolled knew that the facility would be illegal.
However, Indian officials say the students may have been duped.
On Saturday, the Indian ministry of external affairs (MEA) issued a "demarche" to the US embassy in Delhi, expressing concern over the arrests and demanding consular access to those detained.
"Our concern over the dignity and wellbeing of the detained students and the need for immediate consular access for Indian officials to the detainees was reiterated," the ministry said.
It said the students could have been tricked into enrolling and should be treated differently to any recruiters who may have duped them.
"We have urged the US side to share full details and regular updates of the students with the government, to release them from detention at the earliest and not to resort to deportation against their will," MEA added.
Meanwhile a telephone hotline for worried relatives of those being held has been set up at the Indian embassy in Washington, the Times of India reported.
The US embassy in Delhi confirmed it had received the demarche but made no further statement.
It is not the first time US authorities have run such an operation. In 2016, 21 people were arrested after immigration agents set up the fake University of Northern New Jersey. Most of the foreign nationals involved in that scheme came from China and India.
In the latest sting, a website for the University of Farmington showed pictures of students in classes and libraries or relaxing around a grassy campus.
It advertised tuition for undergraduates at $8,500 (£6,500) a year and $11,000 a year for graduate students.
It also had a fake Facebook page with a calendar of events.
But court papers released last week showed that the employees of the University of Farmington were undercover agents for the Immigration and Customs Enforcement agency (ICE).
The "campus" was an office at a business park in a Detroit suburb.
The fake facility was set up in 2015 to try to catch foreign nationals who had initially travelled to the US on student visas and wanted to stay in the country, US media reported.
The indictment, filed in the District Court for the Eastern District of Michigan, said the students knew the scheme was illegal.
"The university was being used by foreign citizens as a 'pay to stay' scheme," prosecutors said.
According to the Detroit News, many of those arrested now face deportation. Eight who allegedly acted as recruiters face federal conspiracy charges for helping at least 600 foreign nationals stay illegally, it added.