In pictures: Migrant caravan begins to cross into Mexico

Mexican authorities for a second straight day block mass entry to a caravan of Central American migrants held up at the border with Guatemala, but accept small groups of women and children for asylum processing, officials say.

A baby cries as a caravan of migrants trying to reach the US, wait to apply for asylum in Mexico at a checkpoint in Ciudad Hidalgo, Mexico, October 20, 2018. (Reuters)

Mexican authorities allowed dozens of women and children from a US-bound Honduran migrant caravan to enter the country Saturday but thousands remain stranded on a border bridge between Guatemala and Mexico where riot police barred their progress.

Mexico's ambassador to Guatemala Luis Manuel Lopez told AFP news agency the women and children would be processed by immigration authorities and taken to a shelter in the city of Tapachula, 40 kilometers away.

Hundreds of others –– tired of waiting on the bridge –– resorted to crossing the Suchiate River below on makeshift rafts and police did not intervene as they clambered up the muddy riverbank on the Mexican side.

Many of them had spent more than 24 hours on the packed bridge where heat and hunger was adding to a growing sense of despair.

Honduran migrants heading in a caravan to the US, hold a demonstration demanding authorities to allow the rest of the group to cross, in Ciudad Hidalgo, Chiapas state, Mexico after crossing from Guatemala, on October 20, 2018. (AFP)

A Honduran migrant, part of a caravan trying to reach the US, is seen after crossing the Suchiate river with the help of fellow migrants to avoid the border checkpoint in Ciudad Hidalgo, Mexico, October 19, 2018. (Reuters)

US President Donald Trump, speaking at a rally in Elko, Nevada, kept up his rhetoric against the migrants and suggested the caravan was politically motivated.

Last week, Trump threatened to cut aid to the region, deploy the military and close the US-Mexican border if authorities did not stop them.

A baby cries as Central American migrants, part of a caravan trying to reach the US, wait to apply for asylum in Mexico at a checkpoint in Ciudad Hidalgo, Mexico, October 20, 2018. (Reuters)

Central American migrants, part of a caravan trying to reach the US., react on a raft after climbing down from a bridge that connects Mexico and Guatemala to avoid the border checkpoint in Ciudad Hidalgo, Mexico, October 20, 2018. (Reuters)

The caravan originated in the Honduran town of San Pedro Sula a week ago, with about 2,000 would-be migrants drawn together by social media.

It is notably different from the "Migrant Viacrucis" organised in April every year by NGOs to draw attention to the plight of Central American migrants.