WASHINGTON — Federal authorities said Thursday they have settled a civil lawsuit against a U.S. apparel importer and two Asian manufacturers, after the affiliated group of companies admitted to engaging in a fraudulent scheme to evade U.S. customs duties.

Motives Inc., a New-York based apparel importer and sales representative for Motives Far East and Motives China Limited, two foreign apparel manufacturers, agreed to pay a $13.4 million civil fine to the U.S. under the False Claims Act, according to American officials.

The companies, all affiliated with a common ownership, admitted to underreporting the value of imported clothing over a four-year period, officials said.

The civil settlement stems from an investigation by U.S. Immigration and Customs Enforcement’s Homeland Security Investigation and U.S. Customs and Border Protection.

Manhattan U.S. Attorney Preet Bharara said: “Motives evaded millions in customs duties by presenting false invoices to U.S. Customs and Border Protection.  With this lawsuit and the accompanying resolution, which involves admissions and the payment of over $13 million, Motives is being held to account for its unlawful evasion of customs duties.”

“Motives disguised the true value of goods imported into the United States to cheat the government out of millions of dollars in customs duties,” said Angel M. Melendez, special agent-in-charge at ICE’s HSI. “This scheme backfired; now Motives will pay millions for trying to skirt America’s customs laws. Trade fraud threatens the U.S. economy and restricts competitiveness of U.S. industry in world markets.”

He added that officials maintain a “zero-tolerance” policy on “predatory and unfair practices.”

According to the government’s complaint, filed in U.S. District Court for the Southern District of New York, the companies “conspired with clothing wholesalers fraudulently to underpay customs duties owed to the government (from 2009 through 2013) by making false representations in entry documents filed with CBP about the value of the imported merchandise.”

The way the scheme worked, according to the government, was Motives Inc. officials presented false commercial invoices to Customs officials that only represented a portion of what they actually paid the foreign apparel manufacturers, thereby understating the value of the imported goods.

A second set of invoices, known as “debit notes” or “cost sheets,” also misstated the value of the merchandise. In a few examples, the government said an importer instructed Motives Far East to deduct the cost of buttons used in making the garment as well as another $2.50 deduction per piece from the total, for the purpose of calculating duties.

The government also cited emails showing that the importer and Motives China Limited discussed deducting $2.50, $3 or $4 per garment for the purpose of calculating the duties.

“Between 2009 and 2013, defendants created numerous debit notes to record the difference between the actual value of garments and the value stated on the commercial invoice,” the government said. “The debit note or cost sheet was not contained in the entry package prepared for the purpose of calculating duty.”

The government estimated that the defendants underpaid customs duties “by millions of dollars over the last 10 years.”

Authorities said the allegations of fraud were first brought to the attention of law enforcement by a whistle-blower who filed a lawsuit under the False Claims Act.