Primus Wireless is among a growing number of mobile virtual network operators seeking to court Americans with roots outside of the United States.

Formed in December, the company has introduced post-paid wireless service for Americans placing calls to India, Korea, Russia and other countries around the world. “No one has really addressed” the international calling market, says Primus Wireless President Jay Rosenblatt, who is one of the founding members of Primus Telecommunications Group Inc., the global telecommunications carrier created in 1994. “We’re fulfilling an unmet need,” Rosenblatt asserts.

Only 5 percent of international calls made from the United States are dialed directly from a wireless phone, according to research firm TeleGeography.

Primus Telecommunications has been marketing long-distance phone service to ethnic groups since 1995. Koreans, Vietnamese and Greeks are among the nationalities Primus has courted.

Its wireless spinoff, which also operates in Australia, Canada and the United Kingdom, now is campaigning to woo Russians and Indians. Russian journalist Alla Baratta is featured on billboards in Brooklyn, N.Y., endorsing the company. New Yorkers with ties to the former Soviet Union can order their wireless services in Russian and make calls to Moscow for as low as 2.9 cents a minute. Billing and customer service are in English.

“People aren’t expecting to get their cell phone bill in Mandarin but when they call up [to order service] … they want to have someone answer in their language,” Rosenblatt says. “That really makes a difference.”

In addition to assigning a traditional phone number, Primus Wireless offers subscribers international digits for $10 per month in 16 countries. That means subscribers can give residents of Brazil, Japan, Hong Kong and other countries a local number to reach them in the United States.

As a mobile virtual network operator, or MVNO, Primus Wireless leases a national wireless network in the United States from an undisclosed carrier, but international calls ride over the global network operated by Primus Telecommunications.

Numerous MVNOs are zeroing in on Americans with ties to other countries, and the competition is getting tougher. The number of MVNOs in the United States more than doubled in seven months from 22 in August to 56 in March, says Max Smetannikov, vice president of business development with Global Advertising Strategies Inc., a marketing consultant.

InPhonic Inc., a public company traded on the Nasdaq National Market, is among the MVNOs. The company recently introduced Viva Liberty, a prepaid wireless operator providing a Spanish language mobile service. Viva Liberty customers will be able to call to Latin and South American countries and elsewhere through one-touch dialing, according to the company.

InPhonic already has experience as an MVNO through its wholly owned subsidiary, Liberty Wireless. The company did not break out numbers at Liberty Wireless or Viva Liberty in its first-quarter earnings.

Washington, D.C.-based InPhonic says there are more than 40 million Hispanics in the United States, but Viva Liberty is not the only mobile operator striving to woo people with ties south of the border. Miami-based TracFone Wireless, for example, caters to Hispanics. The company added 457,000 subscribers in the first quarter to end March with about 4.9 million customers.

TracFone Wireless is a subsidiary of Mexico City-based America Movil, a company with 66.3 million wireless subscribers in the Americas.

“Their view of the Hispanic market is very different from many other people because they know exactly [how] it’s segmented across the border,” Smetannikov says of TracFone. “They know exactly how to target different communities in the U.S.”