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.

"If we, the workers of India, can have the courage to talk to US Congressmen and US federal authorities, then surely the Indian government can do the same so that no other Indian worker suffers as we did," the workers' statement said.

"The Indian government needs to show the kind of courage with the US that it showed in labour talks with Malaysia and Bahrain," said Sony Sulekha, who is on hunger strike. "If we could sit down and talk with the US Congressmen, we believe our leaders can too."

"This hunger strike is a last resort," said Saket Soni, a worker's advocate who directs the New Orleans Workers' Centre for Racial Justice.

The workers are demanding that Indian parliamentarians press their US counterparts for a Congressional investigation into abuses in the US guest worker visa programme.

They also want the ministries of foreign affairs and overseas Indian affairs to press the US State Department to secure the workers' right to participate in a human trafficking investigation into Signal International and its American and Indian recruiters.

"Indian envoy to the US Ronen Sen offered the workers only symbolic reassurances and apologies for protocol. Now they are risking their lives in the hope that the Indian government will find the courage to pressure the US government to grant them dignity, and protect future workers," Soni said referring to a meeting with the envoy in March.