Guatemalan police accompanied by US Immigration and Customs Enforcement agents have swept up the majority of some 300 migrants and taken them back to the Honduran border, dashing their plans to travel to the US in a "caravan".
Near another border point, a different group of about 600 rested at a shelter after crossing the frontier earlier in the day and encountering no resistance from police.
Other, smaller groups were travelling highways elsewhere in a movement involving several thousand people but far different in nature from previous caravans.
The group of 300 migrants - adults, teens and young children - had set out from a shelter in Entre Rios before dawn and walked about six hours before stopping in the town of Morales where they were challenged by police.
They were put on three buses and told they had to go back to register properly at a border station under rules governing freedom of travel in the Central American border agreement between Guatemala, Honduras, El Salvador and Nicaragua.
Guatemalan police said the United States paid for the buses.
The action effectively dissolved what had been the largest and most cohesive group that left the Honduran city of San Pedro Sula on Wednesday in response to a call for the first migrant caravan in many months.
It was nothing resembling the mass human flows that formed in recent years, inspiring the ire of US President Donald Trump.
Guatemala's tactics mirrored those employed last year by Mexico to discourage and break up caravans on its territory following intense pressure from Washington.
Guatemala is stricter about checking documents, and Mexico has deployed thousands of National Guard agents in key corridors to do immigration control.
Asylum seekers who manage to make it to the US border are, after long waits, generally sent back to Mexico to await the outcome of their cases or, more recently, flown to other countries in the region and told their only option is to apply for refuge there.
Australian Associated Press