An estimated 500 migrants and asylum seekers have launched a march in southern Mexico to demonstrate their frustration with the local immigration system.

On Tuesday night, the group left Tapachula, near Mexico’s border with Guatemala, and they continued walking into Wednesday.

Their route followed the path many migrants and asylum seekers take when entering Mexico. The border town of Tapachula has been the site of such protests in the past.

The demonstration was designed to draw attention to the difficulties in applying for legal status in Mexico.

Many participants cited long lines and restrictions on their movements as impediments to finding jobs and accessing legal immigration pathways.

The Southern Border Monitoring Collective, a coalition of civil society groups, also noted that some migrants are being asked to pay nearly $2,300 for documentation in Mexico that is legally free.

Other advocates denounced increased militarisation near Mexico’s borders as threatening the safety of migrants and asylum seekers.

“Without papers, there are no opportunities. We migrants feel like prisoners in Tapachula,” said Joandri Velazquez Zaragoza, a 40-year-old Cuban national.

Mexico has stepped up its immigration enforcement partly as a result of pressure from the United States.

Since returning to the White House for a second term, President Donald Trump has launched a campaign of mass deportation from the US, and irregular border crossings from Mexico into the US have plummeted.

Lawyers for the Trump administration have also reportedly claimed in court that Mexico agreed to accept 6,000 Cubans deported from the US, though they indicated such a deal was a “standing (unwritten) agreement”.

On Wednesday, US District Judge William Young in Boston, Massachusetts, questioned that claim and demanded answers.

“What?” Young wrote in an order on Wednesday. “Can this be true? There’s some unwritten deal between the sovereign nations whereby 6,000 Cuban nationals have already been shipped to Mexico? Is this deal secret?”

The US Department of Homeland Security did not respond to a request for comment from the news agency Reuters.

The Trump administration has repeatedly sought “third-party” countries to take noncitizen deportees. Meanwhile, since January, it has restricted the import of fuel to Cuba, in an attempt to destabilise the country’s government.