Balldev Naidu Ragavan, 47, tried to act as a broker between firearms manufacturers and purchasers between February and September 2006, the report said, quoting the interior ministry.
Naidu has denied the charges, but a Singapore district court ruled that there was sufficient evidence to justify a hearing of his alleged offences in the US.
The report, citing court affidavits, said he conspired to buy and export the firearms illegally from the US to Sri Lanka.
Naidu worked with another Singaporean, 57-year-old Haniff Osman, who was jailed for 37 months by a Baltimore court last year.
Naidu was arrested at his Singapore apartment Sep 22 and was extradited last week, the report said.
Deccan Herald is on WhatsApp Channels| Join now for Breaking News & Editor's Picks