Four Indians and one Pakistani have pleaded guilty to the charges for their part in a major telephone impersonation fraud and money laundering scheme in the US perpetrated by India-based call centres, the US Department of Justice has said.

Three Indians - Rajubhai Patel, Viraj Patel, Dilip Kumar Ambal Patel, and a Pakistani national Fahad Ali - pleaded guilty to money laundering conspiracy before US District Court Judge David Hittner of the Southern District of Texas.

Hardik Patel, an Indian national pleaded guilty to wire fraud conspiracy before the same court on June 2.

Sentencing dates are pending for all five defendants, the Department of Justice said.

Based on the statements in his June 2 guilty plea, beginning August 2012, Hardik owned and managed the day-to-day operations of an India-based scam call centre before later leaving for the US.

According to his June 6 guilty plea, Rajubhai Patel operated as a runner and assisted a co-defendant in managing the activities of a crew of other runners, based primarily out of Illinois, who liquidated victim funds in various locales in the US for conspirators from India-based call centres.