Six Hondurans died and dozens were hurt when a car they were travelling in overturned in southern Mexico. Among those injured Sunday in the road accident in the state of Chiapas bordering Guatemala were four children, the Cuarto Poder news website said.
The caravan, which the United Nations has said is made up of more than 7,200 Central Americans, has crossed into Mexico en route toward the US border, where the migrants hope to gain an asylum.
In a series of tweets earlier on Monday, President Donald Trump said he had alerted the US military and Customs and Border Protection of a national emergency after Mexico was unable to stop the caravan.
Trump also warned last week that if Mexico is unable to keep the caravan from entering the United States, then he will use the US military, not the National Guard, to keep the caravan from coming into the country.