Thousands of migrants march towards Mexico City to protest against detention policies

Migrants also demand justice for 40 victims of fire at Ciudad Juarez detention centre

Migrants walk north on their way to Mexico City from Tapachula, Chiapas state, Mexico. AP

About 3,000 migrants are marching through southern Mexico towards the country's capital to protest against policies that include locking people in detention centres to stop them from reaching the US border.

The caravan reportedly began its journey on Sunday in the city of Tapachula, which borders Guatemala.

Those marching are also demanding justice for the 40 victims of a March 27 detention centre fire in Ciudad Juarez, near the US border.

Mexican media reported that many of the migrants participating in the march come from Central America as well as Venezuela, Nicaragua and Cuba.

The march comes as migrant crossings at the US-Mexico border are on the rise. US Customs and Border Protection last week reported a 25 per cent increase in migrant apprehensions in March compared to the previous month.

Mexican authorities have intercepted previous migrant caravans long before they reached the US border.

The situation at the US southern border is a hot-button political issue and is likely to become a key topic in next year's presidential campaigns.

Former president Donald Trump made slowing immigration, especially at the border, a core policy goal.

He passed a series of restrictive immigration policies, including Title 42, a public health order that allowed border officials to block most migrants from seeking asylum at the border.

Under the policy, most migrants were sent back to Mexico.

Mr Trump also pressured Mexico to do more on the issue. Mexico sent its national guard to its southern border and set up detention centres for migrants.

As a candidate, President Joe Biden pledged to reverse Trump-era migration polices.

But since taking office in 2021, he has struggled to roll out the more humane policies he had promised amid intense Republican resistance.

Instead of scrapping Title 42, the Biden administration expanded its use to include migrants from the previously exempted nations of Venezuela, Cuba, Nicaragua and Haiti.

Title 42 is set to expire on May 11, and border officials are bracing for a surge in arrivals.

Migrants from Central and South America take part in a caravan attempting to reach the Mexico-US border. AFP

Influential Democratic Senator Bob Menendez, who has been outspoken about the need to reform the immigration system, last week presented a set of recommendations that the Biden administration could adopt amid political deadlock on the issue.

He suggested the US create new legal pathways for immigration, as well as expanding existing programmes, adding more border officers, increasing humanitarian assistance to nations that would reduce the incentives to leave, and countering human trafficking networks.

Mr Menendez said it was important to view “what is happening at the border as a strategic challenge to be solved with regional solutions, as well as new border processes instead of just looking at it as a problem”.