More than 1,600 Indians have been caught since the influx began, mainly at the southern tip of Texas, early last year, the Los Angeles Times reported. According to US border authorities, "an undetermined number, perhaps thousands (of Indian immigrants) are believed to have sneaked through undetected," a phenomenon that is "backing up court dockets, filling detention centres and triggering investigations."
The migration is "part of a mysterious and rapidly growing human-smuggling pipeline," the report said.
"The immigrants, mostly young men from poor villages, say they are fleeing religious and political persecution," the report said adding that most of the immigrants say they are from the Indian states of Punjab or Gujarat and have "common surnames" Patel and Singh.
About 650 Indians were arrested in southern Texas in the last three months of 2010 alone.
Indians are now the largest group of immigrants other than Latin Americans being caught at the Southwest border, the report said.
"The suddenness and still-undetermined cause of the Indian migration baffles many border authorities and judges," the report said. The migration is the "most significant" human-smuggling trend being tracked by US authorities, the report quoted deputy director of Immigration and Customs Enforcement (ICE) Kumar Kibble as saying.
"It is a dramatic increase," Kibble said. "We do want to monitor these pipelines and shut them down because it is a vulnerability. They could either knowingly or unknowingly smuggle people into the US that pose a national security threat."
In 2009, the Border Patrol arrested 99 Indians along the entire Southwest border. The journey for many of these immigrants begins from Mumbai to Dubai, then to South American countries such as Ecuador or Venezuela, according to authorities and immigration attorneys.
Guatemala has emerged as the key transit hub into Mexico. "The roundabout journeys are necessary because Mexico requires visas for Indians," the report added.
"They sneak across the dangerous Guatemala-Mexico border and take buses or private vehicles to the closest US-Mexico border. Mexican organised crime groups are
suspected of being involved either in running the operations or in charging groups tolls to pass through their territory," it said.
The report further said that the "Indian migration" mirrors the previous waves of immigrants from far-flung places, such as China and Brazil, who illegally crossed the US border.
The recent trend has also caught the attention of anti-terrorism officials because of the pipeline's efficiency in delivering to America's doorstep "large numbers of people from a troubled region," the report said.
Immigrants, most of whom arrive with no documents, are interviewed by the authorities who want to ensure that "people from neighbouring Pakistan or Middle Eastern countries are not slipping through." However, the FBI and Department of Homeland Security officials said there is no evidence that terrorists are using the smuggling pipeline.
While most immigrants, some of them "Sikhs", claim they fled from India since they were facing "religious persecution," authorities think the immigrants are simply seeking
economic opportunities and are willing to pay USD 12,000 to USD 20,000 to groups that smuggle them to "staging grounds" in northern Mexico.
"Smugglers may have shifted to the Southwest after ICE dismantled visa fraud rings that brought Indians to the Northeast," the report said.
"Political conditions in India don't explain the migration. There is no evidence of the kind of persecution that would prompt a mass exodus," the report quoted analysts as saying.
"There is no reason to believe these claims have any truth to them," political science professor and director of the India Studies Programme at Indiana University Sumit Ganguly was quoted as saying.
The report said hundreds of these immigrants have been released on their own recognisance or after posting bond.
"They catch buses or go to local Indian-run motels before flying north for the final leg of their months-long journeys." The detainees eventually claim asylum. The report quoted a young man as saying that his journey has been "long ... dangerous, very dangerous."
The Indians usually wade across the Rio Grande, and then are shuttled from stash houses to transportation rings that take them to north. David Aguilar, deputy commissioner of Customs and Border Protection, an agency within the Department of Homeland Security, said he believed a high percentage were caught as soon as they crossed the river.
"We very intensely interview, look at their backgrounds, check them against any watch list," Aguilar said, adding that although India is not considered a "special interest" source country for terrorists, the undocumented immigrants are scrutinised as if it were.
Most of the immigrants said they had relatives or friends in the US willing to sponsor them.