Washington: A group of five Indian workers have launched a hunger strike in front of the White House demanding a US Congressional investigation into their "exploitation" by American companies.

The five workers who began the "water only" protest at Lafayette Park opposite the US presidential mansion Wednesday were among more than 500 Indian welders and pipe fitters who allegedly paid up to $20,000 apiece for false promises of green cards and work-based permanent residency in the US.

Seeking "justice from their former employer Signal International and Indian and US recruiters", the workers union claimed the support of the American Federation of Labourers-Congress of Industrial Organizations (AFL-CIO).

"The AFL-CIO and its 10 million members are proud to support the hunger strike by these Signal workers, and their campaign to shed light on the abuses of the US Government's H2B guest worker programme," Jon Hiatt, general counsel for the AFL-CIO, was quoted as saying.

"We know the US is a powerful country, and we know that Signal is a powerful company. That is why we are asking the Indian government to support us as we stand here with our lives shattered," said hunger striker Muruganantham Kandhasami.

The protesters will move to the statue of Mahatma Gandhi in front of the Indian Embassy here Saturday. On May 21, 15 more hunger strikers will join the fast, followed by another 15 on May 28, the organisers said.