A chaotic scene unfolded as a massive caravan of Honduran migrants reached the Guatemala-Mexico border Friday.
A surge of migrants broke through a steel fence that had been padlocked shut. Mexican police in riot gear pushed them back, setting off smoke canisters.
Hundreds of Mexican Federal Police sealed the border as drones and helicopters hovered above the crowd, which waited on a bridge in sweltering heat.
Thousands of migrants are waiting to cross, according to CNN teams at the scene.
At least a dozen migrants stuck on the bridge have jumped into the river below.
It is unclear if they are trying to swim across to the Mexico side of border, go back to Guatemala or just get relief from the crowds on the bridge.
The migrants who remained told CNN they joined the caravan because they had no other choice, noting that they were desperate for work.
Mexican officials had said people seeking asylum would be processed at the border. But it's unclear what will happen next.
Members of the group -- many with children in tow -- had cheered and chanted as they streamed toward the port of entry, with celebratory airhorns blaring.
The caravan formed Saturday in San Pedro Sula, Honduras. Since then, leaders throughout the region have publicly urged them to turn back.
US President Donald Trump has responded with fiery tweets all week, threatening to cut foreign aid to Honduras, Guatemala and El Salvador -- and to send troops to seal the US-Mexico border if the migrants are allowed to reach it.
US Secretary of State Mike Pompeo is meeting with leaders in Mexico City Friday, and the caravan is among the topics on the agenda.
Developing story - more to come