Indian police arrested on Friday 126 people working for a allegedly fake call center making up to $50,000 a day by duping US citizens, officials said.
India became the global call center capital in the early 2000s as foreign firms, drawn by an educated and cheaper English-speaking workforce, farmed out jobs answering customer phone inquiries.
The suspects arrested in Noida outside Delhi would tell Americans there were problems with their social security numbers and solicit money to fix it, police said.
Another scam was telling people they had committed tax offenses and that they had to pay to settle, Noida police official Ajay Pal Sharma told AFP.
"Your warrant is on my desk and if this issue is not resolved we will have to freeze your account and put you behind the bars," one caller is heard to say in a recording made available to AFP.
In Indian-accented English, he says that the man can either fight the US Inland Revenue Service (IRS) in court and face a $75,000 fine as a "tax defrauder" or pay immediately an "out-of-court settlement".
"Many responded to the call and fell for their trap," Sharma said.
The local authorities have also contacted the US Federal Bureau of Investigation and shared the details of the case.
The call center had been in operation for three years. Around 300 computers were seized.
Mumbai police in October 2016 detained more than 770 people suspected of defrauding Americans by impersonating IRS agents and demanding payments.
The US Justice Department subsequently charged 61 people for involvement in India-based schemes that defrauded nearly 15,000 US citizens.
Later in April 2017 they arrested the alleged mastermind of the racket, 24-year-old Sagar Thakkar, who was making more than $155,000 a day at the height of the scam.