The number of Indians arrested for illegally entering the US has nearly tripled so far in 2018, making them one of the largest groups of illegal aliens apprehended, US customs and border protection (CBP) said on Friday.

Paying smuggling rings between $25,000 (Rs 18 lakh) to $50,000 (Rs 36 lakh) per person, a number of Indians are illegally crossing the US-Mexico border and claiming asylum for persecution, CBP spokesman Salvador Zamora said.

Many present viable claims, but a large number are economic migrants with fraudulent petitions that swamp the system and can cause legitimate cases to be “washed out” in the high volume of fraud, Zamora said in an interview.

The Indian embassy in Washington and the Indian consulate in San Francisco did not respond to requests for comment.

Zamora said the CBP expects that the data for the fiscal year that ends on September 30 will show “around 9,000” Indians had been apprehended versus 3,162 in fiscal year 2017.

Around 4,000 Indians who entered America illegally this year did so over a three-mile stretch of border fence at Mexicali, Zamora said.

“The word got out that Mexicali is a safe border city which favours their crossing into the United States,” he said.

Asylum seekers range from lower caste Indians facing death threats for marrying outside their class to Sikhs claiming political persecution, immigration lawyers said.

Fraudulent asylum seekers often present “cut and paste” evidence identical to that of other migrants, Zamora said.

Some 42.2 per cent of Indian asylum cases were denied between fiscal years 2012 to 2017, according to Syracuse University’s Transactional Records Access Clearinghouse. That compares with denial rates of 79 per cent for El Salvadorans and 78 per cent for Hondurans.

After Mexicans, citizens of Guatemala, Honduras and El Salvador were most likely to enter the US illegally in 2018, according to Border Patrol data.