Pakistan, June 15 -- Minutes after an immigration judge rejected his asylum case earlier this week, Oscar Gato Sanchez was arrested as he exited a federal courthouse in Houston.

"I'm a Cuban citizen unjustly arrested," he told AFP as plainclothes officers led him away on Monday.

His aunt Olaidys Sanchez, a 54-year-old legal resident of the United States, sobbed against a nearby wall.

Her nephew was placed in an unmarked gray vehicle that took off with sirens blaring, heading towards an immigrant detention center in Conroe, about 80 kilometers (50 miles) north of Houston, according to official documents.

Gato Sanchez is now among dozens of migrants detained there, awaiting deportation.

In recent weeks, there has been an uptick of immi...