A woman has told how she confronted border patrol agents after they demanded to see her visa documentation while on a bus from California to Nevada.

Tiana Smalls said she was riding the Greyhound from Bakesfield to Las Vegas on June 5 to see family when the altercation took place.

Smalls recalled on Facebook how she challenged the agents for having no authority to check papers so far from a border, after which they backed off.

Tiana Smalls was riding a Greyhound from Bakesfield to Las Vegas to see her family when the driver announced that border agents would be stopping the bus and asking to see documents

The incident took place at a border post which used to be used to check for fruit being brought into California because of an invasive species of fly.

But on this occasion when the bus stopped, Smalls said the driver announced: 'We are being boarded by Border Patrol. Please be prepared to show your documentation upon request.'

Smalls said she stood up and began shouting: 'This is a violation of your Fourth amendment rights. You don't have to show them s***! This is illegal. We are not within 100 miles of an international border so that have no authority to ask you for anything. Tell them to f*** off!'

Not being able to speak Spanish, Smalls said she translated the remark using an app on her phone and tried to reassure Spanish speakers on the bus.

When the agents actually boarded, she reiterated: 'I'm not showing you sh**! I'm not driving this bus, so you have no right to ask me for anything!

'And the rest of you guys don't have to show them anything, either! This is harassment and racial profiling!

'Don't show them a gotdamn thing! We are not within 100 miles of a border so they have no legal right or jurisdiction here! Google it!'

Smalls said she informed everyone on the bus that the agents (file picture) had no authority to demand their papers and that they should refuse to show them

She claims that, after seeing she was willing to cause a problem, the agents got off the bus and allowed it to continue.

Smalls wrote on Facebook that one of the agents told her: 'Fine. We can see that you're a citizen because of your filthy mouth.'

She added: 'These border patrol officers act like they do because they EXPECT people to be afraid of them and just comply.

'The lady next to me spoke NO ENGLISH, but she was a very kind woman. She looked TERRIFIED when they boarded. I felt it was my duty to defend her.

'We DO NOT LIVE in Nazi Germany. No one should be asked to present "papers" for interstate travel. I defended her, and I defended myself.

What is the Fourth Amendment? According to the Fourth Amendment, the people have a right 'to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures.' This right limits the power of the police to seize and search people, their property, and their homes. Today the Fourth Amendment is understood as placing restraints on the government any time it detains (seizes) or searches a person or property. The Fourth Amendment also provides that 'no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched and the persons or things to be seized.' The idea is that to avoid the evils of general warrants, each search or seizure should be cleared in advance by a judge, and that to get a warrant the government must show 'probable cause'—a certain level of suspicion of criminal activity—to justify the search or seizure. Source: National Constitution Center Advertisement

'Use your voice. Take a risk. Act an ASS. Because if you let them intimidate the poor Spanish speaking woman next to you, who do you think they're coming for next?'

According to the ACLU, customs and border officials are legally allowed to operate within a 'reasonable distance' of a US land border.

A 1953 federal regulation defined 'reasonable' to be within 100 air miles, rather than land miles, of a border. That would include the California-Nevada border.

However, the Fourth Amendment only allows law enforcement officials to enter business areas that are open to the public in the exercise of their duties - going anywhere else requires a warrant or consent.

Since Greyhound buses require a ticket to enter, they are not considered to be open to the public, and the agents' legal authority does not extend there.

A statement on the ACLU's website says: 'ACLU affiliates in Washington, California, Arizona, Michigan, New York, Vermont, and Florida have reported multiple incidents involving Border Patrol agents boarding Greyhound buses without a warrant or consent, and terrorizing passengers by demanding their papers.

'These reports indicate that Border Patrol agents routinely engage in racial and ethnic profiling, singling people out for the color of their skin or accents.'

Smalls has been widely praised online for standing up to the agents and defending the passengers who could not speak English.