By JULIA PRESTON

WASHINGTON — About a dozen metalworkers from India staged the fourth week of a hunger strike here this week, camped under a shade tree on Embassy Row.

The workers, who walked off jobs in Gulf Coast shipyards in early March, say they were victims of human trafficking when they were brought to the United States under a temporary guest worker program. The hunger strike is meant to pressure federal officials, and comes as Congress is debating an expansion of the guest worker program, known as H-2B for the type of temporary visa the workers receive.

The Indian workers say they were deceived by Signal International and labor recruiters when they paid as much as $20,000 for visas they believed would allow them to work and live permanently with their families in the United States. In fact, the H-2B visas are for short-term contracts.

“Everyone has a dream,” said one of the protesters, Paul Konar, a 54-year-old worker from the Indian state of Kerala, speaking in Hindi through a translator. “If we could come here legally to live with our families, that was my dream.”

Signal International, a marine oil rig construction company based in Pascagoula, Miss., insists it also was misled about the visas and has filed a lawsuit against the labor recruiters on the Gulf Coast and in India who obtained them for the workers.

“This whole thing got started because of bad recruiting practices,” Richard Marler, the chief executive of Signal, said in an interview. “I wanted these workers to be happy employees. Why would I bring someone in and make them unhappy so they would be less productive in their work?”

Most of the workers, who are metal fitters and welders, lost their legal immigration status when they left their jobs. They adopted the risky strategy of a public hunger strike, they said, to step up pressure on the Justice Department, which has the power to allow the workers to remain in the United States during an investigation of their case.

In a letter this week, three top Democrats in the House of Representatives — George Miller and Zoe Lofgren of California, and John Conyers Jr. of Michigan — asked the Justice Department and immigration officials to investigate the workers’ fraud accusations and offer them protection as victims. The Justice Department this week confirmed it had opened an investigation.

Since May 14, 5 of the 16 workers who participated in the hunger strike have been hospitalized. Mr. Konar fasted the longest, taking no food for 23 days until Thursday, when he was hospitalized with abdominal pain. He was released in the evening.

The Indian workers, among 100 or so who left their jobs in March, were taken to Signal shipyards in Pascagoula and in Orange, Tex., in late 2006 and early 2007. They said they lived in sweltering labor camps, crowded 24 workers to a room, under curfew and restricted from leaving the yards, with $1,050 a month deducted from their paychecks for their upkeep.

They said they learned only after they were here that they would not receive visas, known as green cards, to remain in this country. In March, the workers brought a federal lawsuit against Signal and the recruiters, claiming they were defrauded and exploited.

Among those sued by Signal are Michael Pol, a labor recruiter in Mississippi whose company is Global Resources; Malvin C. Burnett, an immigration lawyer in New Orleans; and Sachin Dewan, a labor recruiter based in Mumbai, India.

Signal executives disputed the workers’ claims, saying they gave medical and other payroll benefits, hired an Indian chef and invested $4 million to provide new modular barracks for the workers at a time when housing was critically scarce along the Gulf Coast after Hurricane Katrina.

Before coming to the United States, many of the Indians had been guest workers in other countries, where, they said, they had never been able to bring their families.

So they jumped at offers by Mr. Dewan’s company, in newspaper advertisements in India and the Middle East, for “permanent lifetime settlement in U.S.A. for self and family,” in the words of one 2004 ad. A copy was provided by the immigrants’ lawyers.

Through Mr. Dewan, the workers said, they initiated applications for employment-based green cards. In one letter, also provided by the immigrants’ lawyers, a worker, Rajan Pazhambalakode, was ordered by Mr. Dewan to pay $4,595 each to Mr. Pol and Mr. Burnett. “The company shall proceed with your green card for the United States of America,” the letter said, referring to Signal.

“I sold my home to raise that money,” said Mr. Pazhambalakode, 43, who is one of the protesters and has a wife and child. “I can’t go home empty-handed because of that great debt.”

Meanwhile, on the Gulf Coast, Signal was seeking skilled workers, overwhelmed with orders for repairs on oil rigs battered by Katrina.

“We were on our knees,” Mr. Marler said, “and we wanted to contribute to turning the Coast around. We were approached by these labor providers, and we jumped at the chance.”

While the workers said they were told they would be entering the United States on temporary visas, they believed that Signal would help them convert to green cards. But in general there is no legal route to switch from a temporary H-2B visa to a permanent green card, which allows immigrants to bring immediate family members.

After arriving at Signal, the workers soon realized the company was not moving to secure any green cards. They maintain that Signal was aware of the recruiters’ visa promises. The company, in its court papers, said its managers learned of the workers’ hopes only when they began to express their discontent.

The workers said the barracks where they were housed were isolated, and company officials told them they would be deported if they left the shipyards.

“It was a scary situation in that company,” Mr. Pazhambalakode said, speaking in Malayalam through an interpreter. They contacted the New Orleans Workers Center for Racial Justice, a nonprofit group. Their lawsuit was brought by the Southern Poverty Law Center.

In a statement, Stephen H. Kupperman, a lawyer for Mr. Pol and Global Resources, said the company “never in any way misled any person, either in India or in the U.S.” He said the contract between the company and Signal ended in 2006.

Ralph R. Alexis III, a lawyer representing Mr. Burnett, said it was his policy not to comment on active cases. There was no answer at telephone numbers for Mr. Dewan in India.