IXTEPEC, Mexico (REUTERS) - Hundreds of migrants hoping to reach the United States boarded a freight train in southern Mexico late on Thursday (April 25), frustrated by efforts to slow their progress by the Mexican government, which is under pressure from US President Donald Trump.

The risky move to board the train, known as "La Bestia" (The Beast), followed a mass breakout of migrants from a holding center in the southern border city of Tapachula on Thursday night.

The government estimated some 1,300 people escaped but said a majority later returned to the centre.

Men, women and children from various countries boarded the slow train as it pulled out of the town of Arriaga in the southern state of Chiapas, Mexican media reported.

Migration authorities said at least 395 people had boarded the train.

The large group descended from the train on Friday after it reached the town of Ixtepec to the north-west of Arriaga.

"We hope our God above will keep helping us. We had to keep moving forwards," said Michael Hernandez, a Honduran, after disembarking.

"They won't let us walk, so we climbed on the train. It's our only option."

Erick Morazan, 28, a Honduran migrant in Zapata, a few towns north of Ixtepec, said he knew several people on the train, adding that he wanted to jump aboard himself.

"I know it's very dangerous, but this is the life of a migrant," he told Reuters by phone.

Trump has threatened to close the US-Mexico border if the administration of President Andres Manuel Lopez Obrador does not put a stop to illegal immigrants reaching the US frontier.

Migrants are paying little heed so far.

The breakout from the Tapachula holding centre was one of the biggest in recent years, and came after Mexico had stepped up efforts to round up and send home migrants.

Video footage of the escape from the Siglo XXI facility posted on social media showed people sprinting from the gates of the holding centre, the biggest of its kind in Mexico.

Migrant advocacy groups say that Mexican officials have been holding 1,700 people there in a space designed for about half that number.

Families of migrants held at the centre say conditions inside are difficult. Detainees, they say, sleep on the hard floor, eat poorly and lack medical attention.

Mexico's National Migration Institute did not reply to requests for comment on conditions at the facility.