Watch: Whistleblower gives Congress emotional warning about Americans being replaced by cheap foreign labor

A whistleblower who helped reveal visa fraud at an Indian tech firm with more than a dozen U.S. locations warned Congress on Tuesday that American workers are routinely being displaced by foreign workers, often with the help of companies who are abusing the visa system.

"They call it knowledge transfer, but we all know that's an illusion," Jay Palmer, a who worked at Infosys, warned the Senate Judiciary Committee today. "It's all about cheaper labor."

Infosys ultimately settled its case with the Obama administration in 2013, and agreed to pay $34 million related to charges that it abused the immigration visa system. Specifically, the company used a type of visa meant only for temporary business travel to the United States as a justification to bring in full-time workers, when it should have used the H-1B visa.

But Palmer said even immigrants who come over under the H-1B visa aren't always skilled workers, as companies usually attest.

"We brought in H-1B workers, it didn't matter if you had skills or not," Palmer said. "We brought them in, I set them in cubicles, and watched the Americans train them, only in the name of the dollar."

He said he was forced to train cheaper labor to do a job that he learned over a few decades.

"I stayed at night and helped these people that came over on H-1Bs learn skills," he said. "They're not skilled workers. These companies bombard our system with H-1B applications, and whoever gets them, they're sent over no matter their skill level. I know, I watched it."

The debate over H-1B visas is part of the larger immigration debate, and many Republicans agree that the U.S. should keep this option open whenever it needs skilled workers. But Palmer's story indicates that the system is being abused to find ways to let unskilled, cheap labor into the United States.

H-1B visas are an issue of agreement for most Republicans and Democrats, although some, like Sen. Jeff Sessions (R-Ala.), say even these need to be closely scrutinized to ensure they aren't used to steal jobs from U.S. citizens.

The broader immigration fight continues to rage on, as the Obama administration is hoping to quickly implement its expanded plan that could give up to 5 million illegal immigrants the right to stay and work in the country. A federal court has blocked Obama's effort, but a federal appeals court is expected to rule shortly, and could decide to allow Obama's plan to be implemented while courts try to settle whether the program is legal.