Nearly three dozen young migrants returning to the US marched openly across the US-Mexico border without papers yesterday.

They are members of a generation brought to the US illegally as children who seek to confront an unjust immigration policy.

Illustrating their childhood and teenage years in the US, they wore a colourful array of graduation caps and gowns from a number of US universities.

The 34 young people, who spent their childhoods in US cities, chanted "undocumented and unafraid" as they crossed the Rio Grande river into Texas.

Customs officials separated them from regular pedestrian traffic before beginning lengthy interviews.

They face what could be weeks in detention and possible deportation as part of the public protest.

At the heart of their protest is a change to US immigration regulations in June 2012 which granted "deferred action" to immigrants who were brought to the country illegally as children.

Those who were within the US in June were told that they could apply for a renewable two-year deferment and work authorisation (Daca).

But the young people crossing on Monday had left the US, either voluntarily or through deportation, months, weeks
or even days before the announcement.

"We look on this action as a type of extension of Daca," said immigration lawyer David Bennion, who was travelling with the group.

"What we would like to see is the people who left, like these 30, who otherwise would have qualified for Daca, to have that be taken into consideration."